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This page summarizes some of my own
deliberations on selecting lenses for my Canon 20D and whatever may follow it.
As such it inherently includes my own bias,
for which I do not apologise, and is presented as is with no warranty, use at
your own risk etc etc.
Read the MTF
Data Overview.
20mm Region
24mm Region
28mm Region
35mm Region
50mm Region
85mm Region A
85mm Region B
100mm Region
135mm Region
200mm Region
There are more issues at shorter focal
lengths than at long, partly because of the more difficult design optimisations,
but also because Canon has a limited range of fixed focal length lenses below
24mm.
The zooms (other than the kit
zoom) perform very well over the APS-C frame but show much more differentiation
over the 35mm format frame coverage where the prime lenses are clearly superior.
Looking at the relative
performances the only really bad (relatively) lens is the 18-55mm kit zoom. The
other zooms fall into the second tier of performance being 10-20% worse than the
primes.
At maximum aperture for many cases the major maximum aperture
differentiation for contrast, detail and bokeh are beyond the frame of APS-C
sensors.
Generally, all the large aperture primes
performed well, even the 28mm f1.8 which had a lacklustre stopped down
performance.
Also take a look at:
Photodo / Canon MTF Cross Validation
It is interesting to find out which lenses
are limiting the image resolution, rather than the sensor being the dominant
limiting factor. To work this out relies on modelling
the lens spatial frequency response as a low pass filter. There are a number
of problems with this, firstly the lens frequency response will be a composite
of several functions and not a simple function. Secondly, Canon have only
provided MTF data for two points, 10 and 30 lp/mm, this is not much to base a
trend on.
So the accuracy of this analysis is limited,
and at best it perhaps provides an indication of how quickly the lens MTF
response decays to minimal contrast, a value of MTF=0.1 is chosen. At worst, the
plots may be trying to squeeze to much data out of too little information and so
be meaningless.
In these plots spatial frequencies (f) above 80 lp/mm are not plotted as this method is probably grossly inaccurate when the MTF gradient between 10 and 30 lp/mm is low.
Sensor resolution is limited to about 40
to 80 lp/mm for the EOS 20D and EOS 1Ds depending on what assumptions are
made in respect if anti-alias filter losses and losses due to geometric
orientation.
This is an important factor in terms of being
able to get the best out of future sensor developments. Clearly sensor
resolution limits are less of a problem for a larger format of a given sensor
resolution.
At 10mm the only information we have is from
the 10-22mm zoom, This seems to be mostly above the sensor limit.
Here some of the lenses are falling below the
sensor limit as the edge of the lens is approached, the 16-35mm zoom seems to be
the worst offender.
Here two zooms show up most significantly as
likely to be a limiting factor, the 24-70mm and the 17-40mm.
Here again the two zooms show up as most
significantly limiting, the 24-70mm and the 17-40mm and also the 28mm f1.8.
Here the most obviously limiting is the
17-40mm zoom.
There are no studied lenses that look likely
to be resolution limiting in this range.
The results of this section are somewhat
suspect and should be treated with some caution.
However, it seems this is only an issue at
and below 35mm with current sensor technology with the most significantly
resolution limiting lenses being zooms down to 24mm focal lengths.
As around 20mm focal lengths, the prime
lenses may start limiting very fine resolution at the edges of the 35mm frame.
This does not generally seem to be a major
issue for APS-C sized sensors at the lens frequency response remains good up to
the edge of the frame.
Note that it is also possible to use this fit
method to estimate the MTF at detail
resolutions higher than 30 lp/mm to scale the 35mm fine detail contrast standard
to the APS-C sensor size, this would be an equivalent resolution of 48 lp/mm
for a 1.6X crop factor sensor. This does not tend to provide much information
over that obtained directly however, as lens performance is less well
differentiated.
Times have changed since I was last in the
market for a lens system. In those days lenses were manual focus, almost
exclusively via linear extension, all lenses indicted the focused distance. Also
almost all (can’t think of any exceptions) included depth of field markings,
even zooms as most were of the trombone style.
Things have changed, now one has to consider
if these features are available or not, plus there is a variety of auto focus
actuators (motors).
Below is a table of lens information for the
lenses studied. Lenses with a mass 700g and over are highlighted in orange,
previous experience shows these become tiresome to use and have around the neck.
Anything over 1Kg is highlighted in red.
See IMATEST and DxO Analyzer for a discussion of these lens test methods.
Make |
Model |
Dia
mm |
Length
mm |
Volume mm^3 |
Mass
g |
Filter
Size |
FE
Rotation |
Focusing |
Reviews / Tests |
CANON |
83.2 |
136.2 |
740481 |
765 |
72mm |
AN |
RFS |
[1] [2] [3] | |
CANON |
82.5 |
112.0 |
598709 |
750 |
72mm |
AN |
RFS |
[1] [2] [3] [4] [5] | |
CANON |
69.2 |
98.4 |
370081 |
390 |
52mm |
AN |
RFS |
[1] [2] [3] | |
CANON |
79.0 |
119.0 |
583299 |
600 |
58mm |
N |
IFS |
[1] [2] [3] [4] | |
CANON |
91.5 | 84.0 | 552418 | 1025 | 72mm | [1] [2] [3] | |||
CANON |
75.0 |
71.5 |
315877 |
425 |
58mm |
AN |
RFS |
[1] [2] [3] | |
CANON |
84.6 |
193.6 |
1088268 |
1310 |
77mm |
|
IFS |
[1] [2] [3] [4] | |
CANON |
86.2 |
197.0 |
1149663 |
1470 |
77mm |
|
IFS |
[1] [2] [3] [4] | |
CANON |
76.0 |
172.0 |
780271 |
705 |
67mm |
N |
IFS |
[1] [2] [3] [4] | |
CANON |
76.0 |
172.0 |
780271 |
7 |
67mm |
N |
IFS |
[1] [2] | |
CANON |
85.4 | 65.5 |
375186 |
545 |
72mm |
[1] [2] | |||
CANON |
73.8 |
50.5 |
216020 |
290 |
58mm |
|
OLE |
[1] [2] [3] [4] | |
CANON |
68.2 |
41.0 |
149776 |
130 |
52mm |
|
OLE |
[1] [2] [3] [4] | |
CANON |
67.4 |
42.5 |
151635 |
210 |
52mm |
|
OLE |
[1] [2] [3] | |
CANON |
83.5 |
77.4 |
423842 |
550 |
72mm |
AN |
RFS |
[1] [2] [3] [4] [5] | |
CANON |
73.6 |
55.6 |
236549 |
310 |
58mm |
AN |
RFS |
[1] [2] [3] [4] | |
CANON |
67.4 |
42.5 |
151635 |
185 |
52mm |
|
OLE |
[1] [2] [3] | |
CANON |
83.2 |
123.5 |
671434 |
950 |
77mm |
|
FFM |
[1] [2] [3] [4] [5] | |
CANON |
EF 24-105mm f/4L IS USM |
83.5 | 107 | 585931 | 670 | 77mm | N | IFS | |
CANON |
83.5 |
77.4 |
423842 |
550 |
77mm |
AN |
RFS |
[1] [2] [3] | |
CANON |
67.5 |
48.5 |
173556 |
270 |
58mm |
AN |
RFS |
[1] [2] | |
CANON |
77.5 |
70.6 |
333041 |
405 |
72mm |
AN |
RFS |
[1] [2] [3] [4] | |
CANON |
69.0 |
66.2 |
247540 |
190 |
58mm |
|
OLE |
[1] [2] [3] [4] [5] | |
CANON |
EF-S
17-55mm f/2.8 IS |
83.5 |
110.6 |
605645 |
645 |
77mm |
|
|
[1] [2] [3] |
TOKINA
|
17mm
f/3.5 AT-X PRO (CANON AF) [1] |
84.0 |
57.0 |
315881 |
435 |
77mm |
|
Internal
Floating Element |
[1] |
CANON |
83.5 |
96.8 |
530076 |
500 |
77mm |
N |
|
[1] [2] [3] [4] [5] [6] | |
CANON |
88.5 | 111.6 | 686589 | 635 | 82mm | N | IFS |
[1] | |
CANON |
EF
16 35 mm f/2.8 L USM |
83.5 |
103.0 |
564027 |
600 |
77mm |
N |
IFS |
[1] [2] [3] [4] [5a] [5b] |
CANON |
83.5 |
89.8 |
491744 |
385 |
77mm |
|
IFS |
[1] [2] [3] [4] |
Make |
Model |
AF
Actuator |
FTMF |
Distance
Scale |
DOF
Scale |
Zoom
Control |
Extends When Zoomed |
Max
Mag |
Closest
Focus M |
Dec 04 Price UOS |
CANON |
EF
200mm f/2.8 L USM MK2 |
USM |
Y |
Y |
Y |
N/A |
0.16 |
1.5 |
£525 |
|
CANON |
EF
135mm f/2L USM |
USM |
Y |
Y |
Y |
N/A |
0.19 |
0.9 |
£699 |
|
CANON |
EF
135mm f2.8 with Softfocus |
AFD |
N |
Y |
Y |
N/A |
0.12 |
1.3 |
£235 |
|
CANON |
EF
100mm f/2.8 MACRO USM |
USM |
Y |
Y |
Mag
Scl |
N/A |
1 |
0.31 |
£394 |
|
CANON |
USM | Y | Y | Y | N/A | 0.95 |
£1449 |
|||
CANON |
EF
85mm f/1.8 USM |
USM |
Y |
Y |
Y |
N/A |
0.13 |
0.85 |
£275 |
|
CANON |
EF
70 200 mm f/2.8 L USM |
USM |
Y |
Y |
N |
RR |
N |
0.16 |
1.5 |
£899 |
CANON |
EF
70 200 mm f/2.8 L USM IMAGE STABILISER |
USM |
N |
Y |
N |
RR |
N |
0.17 |
1.4 |
£1,370 |
CANON |
EF
70 200 mm f/4 L USM |
USM |
Y |
Y |
N |
RR |
N |
0.21 |
1.2 |
£ |
CANON |
EF
70 200 mm f/4 L IS USM |
USM |
Y |
Y |
N |
RR |
N |
0.21 |
1.2 |
£989.95 [Aug 06] |
CANON |
EF
50mm f/1.2L USM |
USM | Y | Y | Y | N/A |
0.15 | 0.45 |
£1149.95 [Aug 06] |
|
CANON |
EF
50mm f/1.4 USM |
MUSM |
Y |
Y |
Y |
N/A |
0.15 |
0.45 |
£250 |
|
CANON |
EF
50mm f/1.8 II |
MM |
N |
N |
N |
N/A |
0.15 |
0.45 |
£69 |
|
CANON |
EF
35mm f/2 |
AFD |
N |
Y |
Y |
N/A |
0.23 |
0.25 |
£219 |
|
CANON |
EF
35mm f/1.4L USM |
USM |
Y |
Y |
Y |
N/A |
0.18 |
0.3 |
£1,099 |
|
CANON |
EF
28mm f/1.8 USM |
USM |
Y |
Y |
Y |
N/A |
0.18 |
0.25 |
£325 |
|
CANON |
EF
28mm f/2.8 |
AFD |
N |
Y |
Y |
N/A |
0.13 |
0.30 |
£140 |
|
CANON |
EF
24 70 mm f/2.8 L USM |
USM |
Y |
Y |
N |
RR |
Y |
0.29 |
0.38 |
£930 |
CANON |
EF 24-105mm f/4L IS USM |
USM | Y | Y | N | RR | Y | 0.23 | 0.45 | £749 Dec 05 |
CANON |
EF
24mm f/1.4L USM |
USM |
Y |
Y |
Y |
N/A |
0.16 |
0.25 |
£950 |
|
CANON |
EF
24mm f/2.8 |
AFD |
N |
Y |
Y |
N/A |
0.16 |
0.25 |
£315 |
|
CANON |
EF
20mm f/2.8 USM |
USM |
Y |
Y |
Y |
N/A |
0.14 |
0.25 |
£339 |
|
|
EF-S
18-55mm f/3.5-5.6 |
MM |
N |
N |
N |
REFE |
Y |
0.28 |
0.28 |
#N/A |
CANON |
EF-S
17-55mm f/2.8 IS |
USM |
Y | Y | N | RR | 0.35 | ? | ||
TOKINA
|
17mm
f/3.5 AT-X PRO (CANON AF) [1] |
|
Focus
Clutch |
Y |
Y |
N/A |
|
0.25 |
£278 |
|
CANON |
EF
17-40mm f/4L USM |
USM |
Y |
Y |
N |
|
N |
0.2 |
0.28 |
£529 |
CANON |
EF
16 35 mm f/2.8L II USM |
USM |
Y |
Y |
N |
RR |
N | 0.22 |
0.28 | |
CANON |
EF
16 35 mm f/2.8L USM |
USM |
Y |
Y |
N |
RR |
N |
0.22 |
0.28 |
£999 |
CANON |
EF-S
10 22 mm f/3.5 4.5
USM |
USM |
Y |
Y |
N |
FR |
N |
0.17 |
0.24 |
£555 |
Characters |
Key |
Y |
Yes |
Y? |
Probably but Canon Data Contradictory |
N |
No |
AN |
Assume No |
OLE |
|
RFS |
|
IFS |
|
FFM |
|
R
EFE |
Ring extending front
element |
RR |
Rear Ring |
FR |
Front Ring |
MM |
Micro Motor |
AFD |
Arc |
USM |
|
MUSM |
Notes |
Explanation |
[1] |
Canon
Version still has aperture ring, no sign of how this is operated on the EF
mount. |
Lens
Characteristic |
Explanation |
FE
Rotation |
Front Element
Rotation: A problem with polarizing or graduated filters. Note Front
group rotational extension |
Focusing |
The focusing method
used in the design. Internal, floating and rear focusing tends to be
preferred and allows more opportunity for the designer to reduce
aberrations across the focusing range, |
AF
Actuator |
The autofocus motor
type. These vary in quality, speed and noise level. General order of
preference from least to most desirable is MM, AFD, MUSM, and USM. |
FTMF |
Full-time
manual focusing. This is for me a major feature, available only with
USM lenses but not all of them. |
Distance
Scale |
A major problem if
not supported as it is then impossible to calculate hyperfocal distances
or depth of field. (see below). |
DOF
Scale |
Depth
of Field or Hyperfocal distance markings. An essential feature for
landscape work. Not a major problem if unavailable for 100mm focal lengths
and above as the DOF is very small anyway. Highly desirable for 50mm and
below. As long as the lens has a focusing distance scale then tables can
be used, although this will be fiddly in the field. |
Zoom
Control |
Almost all seem to be
ring control, either at the front or the back. It is not clear from
Canon’s data if the front element extends or rotates with a front ring control, in
all likelihood it does not. |
Max
Mag |
The maximum lens
magnification in terms of focusing distance, and if applicable zoom
adjustment. |
Closest
Focus M |
The closest focusing distance,
this may be different at different focusing distances for zooms. |
We can see from the lens data table that only
the two short zooms weigh in under the 700g limit and only two longest primes
are just over this limit. In terms of upper body strength requirements the
24-70mm and two 70-200mm zooms make significant demands. I am not sure I could
hold the 70-200mm f2.8 zooms at the ready for very long.
To get a feel for the basics here are some
zoom and prime based systems with totals for volume, mass and cost. There are
lots of combinations and variations not covered but this gives an idea.
Zoom System 1
CANON |
EF
70 200 mm f/2.8 L USM IMAGE STABILISER |
86.2 |
197.0 |
1149663 |
1470 |
£1,370 |
CANON |
EF
24 70 mm f/2.8 L USM |
83.2 |
123.5 |
671434 |
950 |
£930 |
CANON |
EF
16 35 mm f/2.8 L USM |
83.5 |
103.0 |
564027 |
600 |
£999 |
|
SUM |
|
|
2385125 |
3020 |
£3,299 |
Zoom System 2
CANON |
EF
70 200 mm f/2.8 L USM |
84.6 |
193.6 |
1342324 |
1310 |
£899 |
CANON |
EF
24 70 mm f/2.8 L USM |
83.2 |
123.5 |
671434 |
950 |
£930 |
CANON |
EF
16 35 mm f/2.8 L USM |
83.5 |
103.0 |
564027 |
600 |
£999 |
|
SUM |
|
|
2577785 |
2860 |
£2,828 |
Zoom System 3
CANON |
EF
70 200 mm f/4 L USM |
76.0 |
172.0 |
780271 |
705 |
£599 |
CANON |
EF
24 70 mm f/2.8 L USM |
83.2 |
123.5 |
671434 |
950 |
£930 |
CANON |
EF
16 35 mm f/2.8 L USM |
83.5 |
103.0 |
564027 |
600 |
£999 |
|
SUM |
|
|
2015733 |
2255 |
£2,528 |
Zoom System 4
CANON |
EF
70 200 mm f/4 L USM |
76.0 |
172.0 |
780271 |
705 |
£599 |
CANON |
EF
24 70 mm f/2.8 L USM |
83.2 |
123.5 |
671434 |
950 |
£930 |
CANON |
EF
17-40mm f/4L USM |
83.5 |
96.8 |
530076 |
500 |
£529 |
|
SUM |
|
|
1981781 |
2155 |
£2,058 |
Prime System 1
CANON |
EF
200mm f/2.8 L USM MK2 |
83.2 |
136.2 |
740481 |
765 |
£525 |
CANON |
EF
135mm f/2L USM |
82.5 |
112.0 |
598709 |
750 |
£699 |
CANON |
EF
85mm f/1.8 USM |
75.0 |
71.5 |
315877 |
425 |
£275 |
CANON |
EF
50mm f/1.4 USM |
73.8 |
50.5 |
216020 |
290 |
£250 |
CANON |
EF
35mm f/1.4L USM |
83.5 |
77.4 |
423842 |
550 |
£1,099 |
TOKINA
|
17mm f/3.5 AT-X PRO (CANON AF) |
84.0 |
57.0 |
315881 |
435 |
£278 |
|
SUM |
|
|
2610810 |
3215 |
£3,126 |
Prime System 2
CANON |
EF
200mm f/2.8 L USM MK2 |
83.2 |
136.2 |
740481 |
765 |
£525 |
CANON |
EF
135mm f/2L USM |
82.5 |
112.0 |
598709 |
750 |
£699 |
CANON |
EF
85mm f/1.8 USM |
75.0 |
71.5 |
315877 |
425 |
£275 |
CANON |
EF
50mm f/1.4 USM |
73.8 |
50.5 |
216020 |
290 |
£250 |
CANON |
EF
35mm f/2 |
67.4 |
42.5 |
151635 |
210 |
£219 |
TOKINA
|
17mm f/3.5 AT-X PRO (CANON AF) |
84.0 |
57.0 |
315881 |
435 |
£278 |
|
SUM |
|
|
2338602 |
2875 |
£2,246 |
Prime System 3
CANON |
EF
200mm f/2.8 L USM MK2 |
83.2 |
136.2 |
740481 |
765 |
£525 |
CANON |
EF
135mm f/2L USM |
82.5 |
112.0 |
598709 |
750 |
£699 |
CANON |
EF
85mm f/1.8 USM |
75.0 |
71.5 |
315877 |
425 |
£275 |
CANON |
EF
50mm f/1.4 USM |
73.8 |
50.5 |
216020 |
290 |
£250 |
CANON |
EF
28mm f/1.8 USM |
73.6 |
55.6 |
236549 |
310 |
£325 |
TOKINA
|
17mm f/3.5 AT-X PRO (CANON AF) |
84.0 |
57.0 |
315881 |
435 |
£278 |
|
SUM |
|
|
2423516 |
2975 |
£2,352 |
Prime System 4
CANON |
EF
200mm f/2.8 L USM MK2 |
83.2 |
136.2 |
740481 |
765 |
£525 |
CANON |
EF
135mm f/2L USM |
82.5 |
112.0 |
598709 |
750 |
£699 |
CANON |
EF
85mm f/1.8 USM |
75.0 |
71.5 |
315877 |
425 |
£275 |
CANON |
EF
50mm f/1.4 USM |
73.8 |
50.5 |
216020 |
290 |
£250 |
CANON |
EF
24mm f/1.4L USM |
83.5 |
77.4 |
423842 |
550 |
£950 |
TOKINA
|
17mm f/3.5 AT-X PRO (CANON AF) |
84.0 |
57.0 |
315881 |
435 |
£278 |
|
SUM |
|
|
2610810 |
3215 |
£2,977 |
Prime System 5
CANON |
EF
200mm f/2.8 L USM MK2 |
83.2 |
136.2 |
740481 |
765 |
£525 |
CANON |
EF
135mm f2.8 with Softfocus |
69.2 |
98.4 |
370081 |
390 |
£235 |
CANON |
EF
85mm f/1.8 USM |
75.0 |
71.5 |
315877 |
425 |
£275 |
CANON |
EF
50mm f/1.4 USM |
73.8 |
50.5 |
216020 |
290 |
£250 |
CANON |
EF
24mm f/1.4L USM |
83.5 |
77.4 |
423842 |
550 |
£950 |
TOKINA
|
17mm f/3.5 AT-X PRO (CANON AF) |
84.0 |
57.0 |
315881 |
435 |
£278 |
|
SUM |
|
|
2382182 |
2855 |
£2,513 |
To summarise:
System |
Volume
mm^3 |
Mass
g |
Dec
04 Price |
Zoom
System 1 |
2385125 |
3020 |
£3,299 |
Zoom
System 2 |
2577785 |
2860 |
£2,828 |
Zoom
System 3 |
2015733 |
2255 |
£2,528 |
Zoom
System 4 |
1981781 |
2155 |
£2,058 |
Prime
System 1 |
2610810 |
3215 |
£3,126 |
Prime
System 2 |
2338602 |
2875 |
£2,246 |
Prime
System 3 |
2423516 |
2975 |
£2,352 |
Prime
System 4 |
2610810 |
3215 |
£2,977 |
Prime
System 5 |
2382182 |
2855 |
£2,513 |
Summarising relative to the maximum volume or
mass or cost and highlighting the minima and maxima:
System |
Volume |
Mass |
Dec
04 Price |
Zoom
System 1 |
91% |
94% |
100% |
Zoom
System 2 |
99% |
89% |
86% |
Zoom
System 3 |
77% |
70% |
77% |
Zoom
System 4 |
76% |
67% |
62% |
Prime
System 1 |
100% |
100% |
95% |
Prime
System 2 |
90% |
89% |
68% |
Prime
System 3 |
93% |
93% |
71% |
Prime
System 4 |
100% |
100% |
90% |
Prime
System 5 |
91% |
89% |
76% |
So unsurprisingly, we can make the most
savings in volume, mass and cost if we maximally compromise quality.
Clearly there are many combinations including
hybrid zoom and prime combinations.
So in this section I want to take a look at maximum aperture as this is normally thought of as a major advantage for prime lenses. As we have seen, there are some quite fast zooms these days.
A major advantage of wide aperture lenses is
not only their use in low light, but arguably more importantly the ability to
limit depth of field to isolate subjects.
We can see from looking at the equations
that hyperfocal distance is inversely proportional to the f-stop.
In the following section the relative lens speed and depth of field tabulated against f-stop for each focal length of interest are presented. Two depth of field measures are provided. The first the near point of acceptable sharpness when the lens is focused at the hyperfocal distance. The second is the size of the zone of acceptably sharp focus when the lens focus is set to 2M, 5M or 10M depending on the focal length, all worked out for an APS-C sensor.
There is only one image stabilised lens in this study, this is because the IS feature tends to be provided with very long primes or slow zooms. The IS feature is very valuable for handholding or photographing from moving platforms, such as a car or boat. It allows the photography to use two or more stops slower shutter speed and remain handheld. However, this does not help freeze subject motion or limit depth of field. So for this part of the study it is considered of “no consequence”.For zooms for variable speed the speed relevant at the focal length of interest is appended in square brackets.
Another point to note is that a faster lens will often reach an acceptable level of sharpness before a slower lens as it is being stopped down [ref]. This may mean the faster lens providing superior resolution compared to a slower lens, particularly if the speed difference is 2 or more stops.
In this range we have available the following lenses:
Make | Lens | Stops from Fastest Lens |
CANON |
EF
20mm f/2.8 USM |
0.0 |
CANON |
EF-S
18-55mm f/3.5-5.6 |
0.5 |
TOKINA
|
17mm
f/3.5 AT-X PRO (CANON AF) [1] |
0.5 |
CANON |
EF
17-40mm f/4L USM |
1.0 |
CANON |
EF
16 35 mm f/2.8 L USM |
0.0 |
f-stop |
2.8 |
3.5 |
4 |
Near
Point for Set Focus H |
2.75 |
2.20 |
1.93 |
DOF
Set Focus 2M |
1.67 |
2.29 |
2.84 |
One does not normally use a wide angle lens
and try to limit depth of field, however it is important to understand how much
control one may be loosing with a slower lens. There is a reduction of
about 40% in DoF between f4 and f2.8.
Make | Lens | Stops from Fastest Lens |
CANON |
EF
24 70 mm f/2.8 L USM |
2.0 |
CANON |
EF
24mm f/1.4L USM |
0.0 |
CANON |
EF
24mm f/2.8 |
2.0 |
CANON |
EF-S
18-55mm f/3.5-5.6 |
3.0 |
CANON |
EF
17-40mm f/4L USM |
3.0 |
CANON |
EF
16 35 mm f/2.8 L USM |
2.0 |
f-stop |
1.4 |
2.8 |
4 |
Near
Point for Set Focus H |
10.97 |
5.49 |
3.84 |
DOF
Set Focus 2M |
0.37 |
0.75 |
1.12 |
In this range there is a 3.0 stop speed range, this equates to a factor of 3 for depth of field. This focal length is getting close to a normal lens for crop factor 1.6 so both speed and depth of field control is a significant issue.
Make | Lens | Stops from Fastest Lens |
CANON |
EF
28mm f/1.8 USM |
0.0 |
CANON |
EF
28mm f/2.8 |
1.3 |
CANON |
EF
24 70 mm f/2.8 L USM |
1.3 |
CANON |
EF-S
18-55mm f/3.5-5.6 |
2.6 |
CANON |
EF
17-40mm f/4L USM |
2.3 |
CANON |
EF
16 35 mm f/2.8 L USM |
1.3 |
f-stop |
1.8 |
2.8 |
4 |
4.5 |
Near
Point for Set Focus H |
11.61 |
7.47 |
5.23 |
4.65 |
DOF
Set Focus 2M |
0.35 |
0.55 |
0.79 |
0.90 |
A 2.6 stop range and a factor of 2.2 for depth of field, excluding the kit lens. This focal length is fairly close to a normal lens for crop factor 1.6 so both speed and depth of field control is a significant issue.
Make | Lens | Stops from Fastest Lens |
CANON |
EF
35mm f/2 |
1.0 |
CANON |
EF
35mm f/1.4L USM |
0.0 |
CANON |
EF
24 70 mm f/2.8 L USM |
2.0 |
CANON |
EF-S
18-55mm f/3.5-5.6 |
3.3 |
CANON |
EF
17-40mm f/4L USM |
3.0 |
CANON |
EF
16 35 mm f/2.8 L USM |
2.0 |
f-stop |
1.4 |
2 |
2.8 |
4 |
4.5 |
Near
Point for Set Focus H |
23.33 |
16.33 |
11.67 |
8.17 |
7.26 |
DOF
Set Focus 2M |
0.17 |
0.25 |
0.35 |
0.50 |
0.56 |
A 3.0 stop range and depth of field factor of
2.9 excluding the kit lens. This focal length is exactly the normal lens for
crop factor 1.6, so both speed and depth of field control is a significant
issue.
Make | Lens | Stops from Fastest Lens |
CANON |
EF
50mm f/1.8 II |
0.7 |
CANON |
EF
50mm f/1.4 USM |
0.0 |
CANON |
EF
24 70 mm f/2.8 L USM |
2.0 |
CANON |
EF-S
18-55mm f/3.5-5.6 |
4.0 |
f-stop |
1.4 |
1.8 |
2.8 |
5.6 |
Near
Point for Set Focus H |
47.62 |
37.04 |
23.81 |
11.90 |
DOF
Set Focus 2M |
0.08 |
0.11 |
0.17 |
0.34 |
Only a 1.5 stop range and depth of field
factor of 2.1 excluding the kit lens. This is the “ideal” portrait focal
length for crop factor 1.6, so this is critical. The kit lens is particularly
poor speed wise at this focal length.
Make | Lens | Stops from Fastest Lens |
CANON |
EF
85mm f/1.8 USM |
0.0 |
CANON |
EF
70 200 mm f/2.8 L USM |
1.3 |
CANON |
EF
70 200 mm f/2.8 L USM IMAGE STABILISER |
1.3 |
CANON |
EF
70 200 mm f/4 L USM |
2.3 |
CANON |
EF
24 70 mm f/2.8 L USM |
1.3 |
f-stop |
1.8 |
2.8 |
4 |
Near
Point for Set Focus H |
107.04 |
68.81 |
48.17 |
DOF
Set Focus 5M |
0.23 |
0.36 |
0.52 |
A 2.3 stop speed range and a depth of field factor of 2.2. This is a good portrait focal length for crop factor 1.6, so this is critical.
Make | Lens | Stops from Fastest Lens |
CANON |
EF
135mm f/2L USM |
0.0 |
CANON |
EF
135mm f2.8 with Softfocus |
1.0 |
CANON |
EF
70 200 mm f/2.8 L USM |
1.0 |
CANON |
EF
70 200 mm f/2.8 L USM IMAGE STABILISER |
1.0 |
CANON |
EF
70 200 mm f/4 L USM |
2.0 |
f-stop |
2 |
2.8 |
4 |
Near
Point for Set Focus H |
486.00 |
347.14 |
243.00 |
DOF
Set Focus 10M |
0.41 |
0.58 |
0.82 |
A 2.0 stop speed range and 2 depth of field factor. Depth of field is becoming limited anyway at these focal lengths so this is less of an issue.
Make | Lens | Stops from Fastest Lens |
CANON |
EF
200mm f/2.8 L USM MK2 |
0.0 |
CANON |
EF
70 200 mm f/2.8 L USM |
0.0 |
CANON |
EF
70 200 mm f/2.8 L USM IMAGE STABILISER |
0.0 (- 2.0 for IS) |
CANON |
EF
70 200 mm f/4 L USM |
1.0 |
f-stop |
2.8 |
4 |
Near
Point for Set Focus H |
380.95 |
266.67 |
DOF
Set Focus 2.0M |
0.26 |
0.38 |
A 1 stop speed range and 1.4 depth of field factor. Depth of field is becoming limited anyway at these focal lengths so this is less of an issue
The most significant trade-offs are in the normal to moderate telephoto range, 24 to 85mm.
Focal
Length Group
|
Type |
Applications |
Requirements |
10mm |
Ultra
Wide |
Landscape,
Strong Perspective Abstracts, Strong Perspective Nature, Wide View
Architecture |
Excellent
Detail, minimal flair and distortion. Speed not an issue. |
17mm,
20mm |
Wide |
Landscape,
Moderate Perspective Abstracts and Nature, Architecture, People |
Excellent
Detail, minimal flair and distortion. Speed a secondary issue. |
24,
28, 35mm |
|
Landscape,
Still Life, People, General |
Good
Detail and contrast well controlled flair, speed very significant. |
50mm |
Short
Telephoto |
Landscape,
Still Life, Portrait, General |
Good
Detail and contrast, well controlled flair, speed highly significant |
85mm,
135mm |
Medium
Telephoto |
Landscape,
Still Life, Portrait, General, Nature, Architecture Detail |
Good
Detail and high contrast, speed highly significant |
200mm |
Long
Telephoto |
Landscape,
Still Life, Portrait, General, Nature, Architecture Detail |
Good
Detail and high contrast, speed significant |
There is not a tremendous difference in the angle of view from 20mm to 17mm as can be seen from this example framing.
Looking at the way the focal lengths line up based on the core lenses of the 100mm f2.8 Macro and 50mm f1.4:
This suggests that the 28mm lens may be a better choice for an intermediate focal length between 20 and 50mm than 35mm
The aim of this section is to review the stopped down (f/8) performance of the available EF-S lenses not studied against some of the lenses already reviewed.
At the time of writting the first prime EF-S
lens has just been released. If a wide range of fast EF-S lenses are produced in
the future they may be worth investigating.
This lens’s contrast is much worse that the
kit lens at the wide end except for beyond about 11.5mm from optical axis. There
is less separation with detail, although this is much worse than the kit lens
and probably worse than the disappointing 16-35mm zoom for detail.
The 17-85mm is about the same for contrast
and detail as the 17-55mm kit lens, i.e. not that good at the edge, both
probably the worst lenses out of the group.
The 60mm Macro performs better, keeping up
quite well for contrast with the prime lenses out to about 10mm off the optical
axis. Detail for this lens is very good at the centre but degrades fast being
worse than the 100mm f2.8 macro beyond about 7.5mm from the centre of the
optical axis.
Another possible use of the 60mm Macro is as
a portrait lens so the next few plots look at the wide open performance of the
lens including the MTF influence on Bokeh.
We can see from this that the indications for
Bokeh are very good and the wide open contrast and detail performance is better
than all the other lenses. However, it must be noted than the f2.8 aperture is
much smaller than the 50mm primes. However it is beating the more comparable
100mm f2.8 Macro.
The performance is better at the tele end
keeping up with the prime lenses for contrast to 6 or 7mm off optical axis after
which it drops off quickly being the worse performer by far beyond 9mm from the
optical axis.
A similar story is seen for detail with the
only exception that the detail contrast below 4mm offset from the optical axis
is the best out of the lenses, however it degrades rapidly and is the worst lens
by a long way by 9mm offset from the optical axis.
The EF-S 17-85mm f4-5.6 IS USM is
disappointing and typical of a wide range zoom, however it is relatively light
and compact if performance is not a major issue.
The EF-S 60mm f2.8 Macro USM is better and
should be very sharp and high contrast in the centre of the frame although poor
at the edge, personally I think the 100mm f2.8 is a better solution in some
ways. The EF-S 60mm could make quite a good portrait lens with a reasonable
maximum aperture and excellent wide open detail and contrast and good bokeh.
Zooms
are ideal for walking about general photography. It has to be said that the
18-55mm kit zoom probably fills this role well despite its shortcomings.
A
major advantage of zooms with a DSLR, is reducing the number of lens changes and
thus the chances of dust contamination. Looking at the available zoom ranges
(excluding the kit lens):
Available
Zoom Sizes |
Effective
Focal Length on 1.6X Sensor in 35mm full frame terms |
70-200
mm |
112-320
mm |
24-105mm | 38mm-168mm |
24-70
mm |
38-112
mm |
17-40
mm |
27-64
mm |
16-35
mm |
26-56
mm |
10-22
mm |
16-35
mm |
I
know in general photography on full frame 35mm I tend to want to swap between 28
and 85mm the most. I can see here that the zooms available would not reduce the
number of the changes greatly. Below 70mm each zoom is only replacing about two
to two-and-a-half prime lenses, so I will still be changing lenses quite a lot.
One tempting zoom is the 17-40mm f4L. This seems to be a very sharp lens with a good reputation which could cover the requirements of the 20mm and 35mm lenses for a similar total weight, cost and slightly less volume. One issue with wide zooms is barrel distortion.
For 1.6X crop factor cameras the excellent EF-S 10-22mm provides a small aperture good quality ultra wide to normal zoom. A good companion to this would be either the 24-70 or 24-105mm zooms providing a two zoom system covering the most used focal lengths. When augmented with the 18-55mm kit lens then overlap is provided around the normal range.
Looking to the future a 24-70 or 24-105 will provide an ideal walk around lens for full frame and the 17-40 will replace the 10-22.
Other reasons for zooms:
i) Minimize resolution loss due to cropping.
This is not really such an issue due to the improvements in sensor resolution. In most cases it just requires the photographer to walk a little anyway.
ii) Optimize Framing
Again not really - see above. In fact when I use a zoom I find the zoom is a bit of a distraction to working out the composition and experimenting with different views and perspectives.
iii) Reduce Weight
This is just not the case. Zoom systems of inferior performance and speed tend to weigh just as much or more as a prime system, they probably cost the same also. Also zooms tend to be heavy lenses as can be seen from some of the comparisons here.
iv) Allow you to deal with rapid changes of focal length.
This is true, particularly if you are in a photo-journalistic activity. You can get around this to quite an extent by cropping but this is not ideal. Of course a zoom only helps here if you don't have to go beyond the limits of it's focal length. There are some very wide range zooms with advanced optical designs, they are not very sharp though. This does not describe my sort of photography though. (But I do have the little kit zoom; you see this has all been planned!)
The only really viable option is the 10-22mm zoom.
There is an abundance of riches in some ways.
The 16-35mm zoom is fast but limited in sharpness, however this problem is most significant for 35mm full frame use rather than APS-C format. Another issue with this lens is it may be the limiting factor for sharpness instead of the sensor when comparing the Canon simulated MTF data. Note that some more modern zoom designs may exhibit lower chromatic aberration for full frame DSLRs, the 16-35mm may be an example of this (Full frame with digital and Chromatic Aberration).
Even stopped down the 16-35 has less centre detail than the 17-40 and wide open on full frame the performance is so poor as to be not worth the trouble [1]. An interesting exerisise though was printing the sample prints in this review as if from the 5D or truncated to APS-C. Although to me at A3+ and even A4 the 17-40 @ 17mm was sharper than the 16-35 @ 16mm both f5.6 my wife and son had trouble in telling the difference and in fact picked the 16mm.
The results of [1] for the 5D with 16mm f2.8 at f2.8 and f5.6 were scalled to 5606 pixels width to set the pixel resolution equivalent to a 20D with a full frame sensor using bicubic smoother. Then, from the results of SLRGear, the f5.6 image was given 2, 3 and 4 Blur More operations to simulate the measured effect at the edge of the APS-C sensor of the 20D. All frames were then scaled to give a APS-C sensor sized view at A4 using Bicubic Sharper, given standard output sharpening of dark and light highpass filter layers with a r=1.1 pixels and printed on Matt paper.
The SLRGear results suggest only a 2 DxO BxU variation between the f5.6 corners and f2.8 corners on a 20D. However even the four blur more example was not as bad as the f2.8. This suggests that the example in [1] was a bad copy and the SLRGear a good copy, or possibly the effect of BxU are not calibrated correctly. This is not encouraging as the performance of the SLRGear lens was thought to be poor.
The 17-40mm zoom is sharper (the lens image simulations for this lens are just detectably sharper than the 20mm and 35mm primes at f/8) but of average speed at this focal length.
Both prime lenses are said to have lower spherical aberration levels by a factor of 3 to 4 than the zooms [1] [2] [3] [4] although there is some disagreement [2], this is particularly important for architectural use. Additionally the zooms have no depth of field markings.
The Tokina 17mm may be slightly sharper than the Canon 20mm, but the latter has USM and FTMF.
A 20mm lens angle of view is only slightly narrower than 17mm, and there is the issue of future compatibility that is more problematic with third party products.
It comes down I think to the 17-40mm zoom or the 20mm prime, it is a close thing. For me the advantages of the prime in faster aperture, depth of field markings and weight swing things. The aperture of the zoom at other ranges will be limiting but not excessively so at 20mm.
Also with the recent release of the 5D and the prospect of affordable full frame DSLRs sooner than expected the 17-40's limited aperture is less of an issue in the longer term. One is thus tempted to forgo the 1 stop speed and other small advantages of the zoom for an increase in cost and weight to gain the flexibility of the zoom. A fast aperture lens in the 24-35mm range can still be provisioned.
This lens test is about the most comprehensive and objective lens test I can find and directly compares the 17-40mm f4L with the 20mm f2.8. In this test the 20mm comes in slightly sharper, with lower spherical and chromatic aberration and less vignetting. The 20mm seems to be able to provide reasonable corner full frame sharpness, at least better than the 16-35mm.
It is worth noting there is significant part to part variation, this is most obvious below 35mm focal lengths where the lens design difficulties highlight any poor variation. So for example the 17-40 and 20mm should on average be sharper than the 16-35mm there will be some individuals that have experienced parts with the opposite ordering.
The EF-S 17-55mm f2.8 IS seems to have good MTF performance compared with other lenses in this class. It is quite heavy and expensive for an EF-S lens. However it may be a good choice for those that do not plan to move from crop sensors to full frame.
These are candidate focal length for normal lenses for a 1.6X crop factor camera.
The sharpest lenses are the 35mm primes.
The 28mm primes and the 24mm primes in between in terms of sharpness.
For the primes the slowest lenses in any given focal length are the sharpest at f/8. However, the faster lenses have USM and FTMF, this is a significant compromise for the 28mm f1.8.
The clearly superior lens is the 35mm f1.4L, however this is a weighty and expensive lens.
Of the zooms in this range the 24-70mm is the sharpest, but even so is mostly outclassed by the primes. Additionally it is a very heavy lens. It was worth noting the review [SLRGear] showed that although the APS-C performance at 24mm was very good there was significant degradation in the corners and edges on full-frame wide open.
If you must have a zoom go for the 24-70. If you have the budget and weight is not a problem, go for the 35mm f1.4L. Otherwise consider the 28mm f1.8. If lens speed and autofocus performance is not a major issue go for the 35mm f2. I am inclined to save for the 35mm f1.4L, but it is heavy so the 28mm f1.8 may be better.
A late assessed lens is the 17-40mm f4L. This is a very sharp lens with a good reputation.
If the 50mm and 20mm focal lengths are taken as given then the 28mm lens would be the best intermediate fit.
The EF-S 17-55mm f2.8 IS seems to have good MTF performance compared with other lenses in this class. It is quite heavy and expensive for an EF-S lens. However it may be a good choice for those that do not plan to move from crop sensors to full frame.
This is a no brainer, the 50mm f1.4 is blisteringly sharp, has USM and FTMF and is small light and reasonably priced.
The 50mm f1.8 is good optically but with no distance scale limited. A good value budget lens if build quality is not important.
Of the zooms in this range the 24-70mm is the sharpest again.
The EF-S 60mm f2.8 Macro performs well but not as well as the 50mm primes or the 100mm f2.8 Macro and is good at maximum aperture.
The EF-S 17-55mm f2.8 IS seems to have good MTF performance compared with other lenses in this class. It is quite heavy and expensive for an EF-S lens. However it may be a good choice for those that do not plan to move from crop sensors to full frame.
The 85mm f1.8 is an exceptionally good lens. There is a faster L class lens (the f1.2L), however it is very heavy and expensive so it has been neglected in this study as the f1.8 ticks all the boxes.
Both the 24-70mm zoom and the three 70-200mm zooms are good, but come no where near this lens (or the 100mm f2.8 Macro I already have).
All the zooms are heavy, extremely heavy in the case of the 70-200mm f2.8 pair. I know that these would be exhausting to use without a tripod and the IS version would be needed if only because my arm would start shaking early on.
Of the two primes the 135mm f2 is much better than the f2.8 softfocus in resolution terms, but at a price and weight.
The 135mm f2 is on a par weight wise with the 70-200mm f4, if you need a long zoom then that is the one to go for.
However, in terms of optical quality the 135mm f2 is well ahead of the zooms particularly in edge detail.
Here we have the one lone prime against the four zooms. In terms of image quality there is not much between them. In terms of weight the prime is similar to the f4 zoom although this f4 zoom is the less sharp of the group, the IS version is almost the same in terms of sharpness as the non-IS except for f8 30 lp/mm where the non-IS has superior microcontrast across the frame.
For me, the prime has it due to the speed weight trade. However, one of the f4 zoom would be an excellent alternative to the 135mm f2 and 200mm f2.8 if maximum kit weight is a major issue.
A point to remember is the f/2.8 lenses can be used with a 2X teleconverter and still retain autofocus on the 20D (the limit is f/5.6). The f/4 lens can only use the 1.4X teleconverter and retain autofocus. The mass of the teleconverters is 265g and 220g respectively further adding to the mass and length of the lens. However, in probability use will entail a tripod on these focal lengths.
It seems that the primes are there with the performance. However, the smaller aperture zooms come in well if all up weight needs to be kept low.
The wide aperture zooms are good image wise (with the possible exception of the 16-35mm, however this is not too bad for APS-C sensors) but are very heavy to deal with on camera. If you have the upper body strength this may not be an issue for you.
There is an argument that the 17-40 provides improvement in sharpness over the kit lens only at the normal to long lengths but no speed advantage and so a better selection of zooms might be the 10-22 with either the 24-70 or 24-105mm zooms. These could be augmented with fast primes.
I feel that maximum apertures are well worth the compromises for the creative control the allow.
If budget is unlimited then a dual zoom and prime system gives the best of both world, just choose what you need before you leave the house (in my dreams).
In practice as I have the 100mm f2.8 Macro, this for the moment double for the 85mm and 135mm, allowing me to concentrate on populating the extremes of focal length and perhaps the 50mm and 20mm.
Last Updated 05/06/2008
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