The crop factor of digital SLR's
by Fred Kamphues
A lot of people ask me about the crop factor of current DSLR's.
I will explain this below, using an example of a 35 mm slide of the Gullfoss waterfall in Iceland and a similar Nikon D1X image.
Both images were made with a Nikkor AF-S 17-35 mm zoom lens at the same focal length.
Nikon F90X
Nikkor AF-S 17-35
at 25 mm focal length
35 mm slide film
Nikon D1X
Nikkor AF-S 17-35
at 25 mm focal length
23.7 mm CCD sensor
The field of view reduction of the digital camera is obvious.
This is also known as the crop factor.
A 25 mm lens on a DSLR camera is no longer a wide angle lens, but corresponds to a 37 mm lens on a 35 mm film body.
The D1X has a sensor size of 23.7 x 15.5 mm.
This sensor size is sometimes referred to as APS size.
As a result the effective field of view is 35/23.7 = 1.5 times smaller.
This is indicated in the picture below.
Comparison of field of view with a 35 mm film camera and an DSLR camera with APS size sensor
If you want to make wide angle pictures with a digital SLR with APS size sensor, you need a much shorter focal length than you normally would with a 35 mm camera.
This is shown below. The DSLR image is taken at 17 mm focal length, the 35 mm slide was taken at 25 mm focal length. Both images have roughly the same field of view.
Nikon D1X
Nikkor AF-S 17-35
at 17 mm focal length
23.7 mm CCD sensor
Nikon F90X
Nikkor AF-S 17-35
at 25 mm focal length
35 mm slide film
No crop factor
The following DSLR cameras have a full frame sensor (appr. 36 x 24 mm) and no crop factor with respect to 35 mm film camera:
Canon 1Ds series, Canon 5D series
Nikon D3, D3S, D700, D3X
Sony Alpha 900, Alpha 850
Crop factor 1.3
The crop factor of the Canon 1D series bodies is approximately 1.3.
Crop factor ~1.5
The following DSLR cameras have APS size (appr. 23 x 15 mm) sensors:
Canon D30, D60, 300D, 350D, 400D, 450D, 500D, 550D, 10D, 20D, 30D, 40D, 50D, 1000D.
Fuji S1 Pro, S2 Pro, S3 Pro, S5 Pro.
Nikon D1, D1X, D1H, D100, D2H, D2Hs, D2X, D2Xs, D40, D40X, D50, D60, D70, D70s, D80, D90, D200, D300. D300S, D3000, D5000.
Pentax *istD, *istDS, *istDL, *istDS2, *istDL2, K110D, K10D, K100D, K100D Super, K200D, K20D, K2000, K-7. K-x.
Samsung GX-1S, GX-1L, GX-10, GX-20, NX10,
Sony Alpha DSLR A100, A200, A300, A350, A700, A230, A330, A380, A500, A550. A450.
The crop factor of above mentioned DSLR bodies is approximately 1.5.
Nowadays a large range of ultra wide angle zoom lenses is available, to satisfy the needs of the digital photographer:
For Nikon and Fuji DSLR bodies, the following (ultra) wide zoom Nikkor lenses are available:
Nikkor:
AF-S 14-24 f/2.8G
AF-S 17-35 f/2.8
AF 18-35 f/3.5-4.5
And with reduced image circle for APS size sensors only:
AF-S 10-24 f/3.5-4.5G DX
AF-S 12-24 f/4.0G DX
AF-S 16-85 f/3.5-5.6 VR DX
AF-S 17-55 f/2.8G DX
AF-S 18-55 f/3.5-5.6G DX
AF-S 18-55 f/3.5-5.6GII DX
AF-S 18-55 f/3.5-5.6G DX VR
AF-S 18-70 f/3.5-4.5G DX
AF-S 18-105 f/3.5-5.6G DX VR
AF-S 18-135 f/3.5-5.6G DX
AF-S 18-200 f/3.5-5.6G DX VR
For Canon DSLR bodies, the following Canon (ultra) wide zoom lenses are available:
EF 16-35 L USM f/2.8
EF 16-35 L II USM f/2.8
EF 17-40 L USM f/4
And with reduced image circle for APS size sensors only:
EF-S 10-22 USM f/3.5-4.5
EF-S 17-55 IS USM f/2.8
EF-S 17-85 IS USM f/4.0-5.6
EF-S 18-55 f/3.5-5.6
EF-S 18-200 f/3.5-5.6 IS
For both camera brands the following third party zoom lenses are available:
Sigma:
12-24 f/4.5-5.6 EX DG
15-30 f/4.5-5.6 EX DG
17-35 f/2.8-4.0 EX DG
And with reduced image circle for APS size sensors only:
10-20 f/4-5.6 EX DC
10-20 f3.5 EX DC HSM
17-70 f/2.8-4.5 DC Macro
17-70mm F2.8-4 DC Macro OS HSM
18-50 f/2.8 EX DC
18-50 f/3.5-5.6 DC
18-50 f2.8-4.5 DC OS HSM
18-125 f/3.5-5.6 DC
18-125 f/3.5-5.6 DC OS HSM
18-200 f/3.5-6.3 DC
18-250 f/3.5-6.3 DC OS HSM
Tamron:
SP AF 17-35 f/2.8-4.0 Di LD
And with reduced image circle for APS size sensors only:
SP AF 10-24 Di-II
SP AF 11-18 f/4.5-5.6 Di-II LD
SP AF 17-50 f/2.8 XR Di-II LD
AF 18-200 f/3.5-6.3 XR Di-II LD
AF 18-250 f/3.5-6.3 IF Di-II LD
AF 18-270 f/3.5-6.3 Di-II VC
Tokina:
With reduced image circle for APS size sensors only:
AF 10-17 f/3.5-4.5 FishEye DX
AF 11-16 f/2.8 AT XD
AF 12-24 f/4.0 AT-X PRO DX
AF 16-50 f/2.8 DX