Behaviors of SLR Lenses on Canon APS-C

Field of View
Comparison of the field of view you get at various focal lengths and lenses. It's easier to visualize with pictures. The camera is a Canon Rebel T2i (aka 550D) which has an APS-C sensor (1.6 crop factor). Camera is tripod mounted while lenses are changed. Sorry, I forgot to take "normal" range photos with the zoom. I'll do a second set of tests for that. These still images are at 4:3 Aspect Ratio. Video mode will crop the top and bottom to form a 16:9 image.

11mm (17.6mm effective)
Tokina 11-16 AT-X Pro 2.8 (Zoom)

16mm (25.6mm effective)
Tokina 11-16 AT-X Pro 2.8 (Zoom)

18mm (28.8mm effective)
Sigma 18-50 EX DC Macro 2.8 (Zoom)

50mm (80mm effective)
Sigma 18-50 EX DC Macro 2.8 (Zoom) 

50mm (80mm effective)
Nikkor SC 50mm 1.4 (Prime), adapted from F-mount to EF
Note how the view is narrower than the Sigma above.  Infinity focus is slightly before the infinity marker on the lens.

70mm (112mm effective)
Canon EF 70-200 F2.8/L IS (Zoom)

85mm (136mm effective)
Canon EF 85mm 1.8 (Prime)

200mm (320mm effective)
Canon EF 70-200 F2.8/L IS (Zoom)








Focus Breathing
A slight change of FOV may be observed when changing focus.  All the SLR lenses from the previous test exhibit this to some degree.

Focused to Foreground
Note the trees on either side of the picture.  Focus to foreground which is about 9 feet away shows less of trees on either side.  Lens is a Canon EF 70-200 F2.8/L IS at 70mm.

Focused to Background
Focus to background shows more of the trees on either side.  Lens is a Canon EF 70-200 F2.8/L IS at 70mm.







Lenses Tested
Tokina 11-16MM F/2.8 ATX 116 Lens for Canon EOS AF Digital - Tokina ATX116PRODXC (paid link)
Sigma 18-50mm f/2.8 EX DC SLD ELD Aspherical Macro Lens for Canon Digital SLR Cameras (paid link) 
Canon EF 85mm f/1.8 USM Medium Telephoto Lens for Canon SLR Cameras (paid link) 
Canon EF 70-200mm f/2.8L IS USM Telephoto Zoom Lens for Canon SLR Cameras (paid link) 

Protecting the Canon WD-H43 Wide Angle Lens

DIY WD-H43 Filter Adapter with UV Filter and White Balance Cap

The WD-H43 has no filter ring and uses a strange cap size. As it is there is little to protect the nice high definition lens from stray projectiles, sea spray, leaves, and twigs. I like to shoot outdoors romping merrily through grass, twigs and branches while grown men with toy guns lob tiny plastic pellets at upwards of 280fps. Needless to say I was worried for my lens.

So I asked around but found no easy answers to solutions. Someone did point me to a CAVision lens clamp to adapt 75mm lens, the WD-H43 is 74.5mm which is close enough, to 77mm which I ordered from my favorite camera store. That was late September 2007. It's been on backorder since then and delivery won't happen until middle of 2008 if all goes well. Naturally I was frustrated in not being able use the lens with the great abandon I prefer. I tried a few ideas to hold a filter including using rubber plumbing parts. Finally I've come up with an interim solution that works.


A failed experiment

I use a spare lens cap for the WD-H43 and then cut out a hole for the lens. I glued a 77mm filter ring on to it then mounted my choice of 77mm filter. In this case I chose a low profile 77mm UV multicoated filter like those used in DSLRs. I did some experiments on how deep a stack I could use without the rings showing in the footage and the most it might do ('m guessing) is two. It would be three if I kept the glass on the glued on ring but I didn't. I shot test video which will be posted at a later date. Update: The LCD doesn't show the overscan area so it appears that more than 1 ring on the stack would be visible in the footage. Not one wanting to crop good video out, I put the filter glass back on.

For now here's some pictures to give you an idea of what it looks like.


DIY WD-H43 Filter Adapter with UV Filter without the White Balance Cap

DIY WD-H43 Filter Adapter with UV Filter only

DIY WD-H43 Filter Adapter with UV Filter and White Balance Cap

Static Adapter Version 2

I broke my vibrating motor while disassembling it from the 52mm tube. I had constructed a ground glass holder by cutting up a plastic key card and slipping it into an empty 52mm filter ring. Mounted backwards it mated with a 52mm-to-52mm macro coupler. Unfortunately it didn't work because there wasn't enough play to vibrate the ground glass. Incidentally, the test tape was somehow lost as I changed tapes. And later I had an accident that broke one of the small gauge wires on the motor. I get knocked down, but i get up again.

So I took the 52mm filter plus mount I made for the failed vibrating experiment and moved it to the 57mm. Incidentally a 52mm filter fits snug in that macro tube so it was easy to position and get to the right distance. Add a +10 singlet macro and some step down and I was in business. This was also the perfect chance to try my brand spanking new camcorder.




Say hello to the Canon HV20. It's a small HDV camcorder with a progressive CMOS sensor. The little wonder reminds me of my Canon Elura which was one of few early MiniDV with a progressive CCD. Against all advise, I hooked up my Static Adapter to both the ZR200 and HV20. Their resolution and light gathering abilities are different. I just wanted to see how bad the grain could be with this unit. One other thing changed on the V2, I have a +10 singlet close-up macro (not an achromat). The shot was done indoors on a cloudy day.



Lens: 50mm Nikon Series E f/1.8
DOF Adaptor: YouSillyMan35 v2 Static, Nikon F3 Type D
Camera: Canon HV20, 1/2.7" Single CMOS progressive
Original Mode: HDV24PF, TV-48
Recompression: WMV9 1920x1080 30fps progressive, 6Mbps
File Size: 71.24MB
http://www.megaupload.com/?d=9G3EUNE5

Lens: 50mm Nikon Series E f/1.8
DOF Adaptor: YouSillyMan35 v2 Static, Nikon F3 Type D
Camera: Canon ZR600, 1/6" Single CCD interlaced
Original Mode: DV interlaced, automatic
Recompression: WMV9 720x480 29.97fps interlaced, 4Mbps
File Size: 45.84MB
http://www.megaupload.com/?d=3N8MNZ2B