For Drisley: Tokina 17 mm ATX PRO

[tommykjensen]

As previous of the lens Tokina 17 mm ATX PRO I need Your opinion because I am a bit concerned about the used Tokina 17 mm I bought recently.

I did some testshots in my livingroom, used tripod, timer and mirror lockup. Had a few lamps lighting up the room and also tested my 28 mm, 50 mm and 85 mm the exact same way. All shot wide open and all focused on the middle box.

Can You tell me if the Tokina is backfocusing? It looks like it to me or is this what is to be expected from this lens wide open? :( Or was the test completely wrong and the cause of the bad result?

http://photo.klein-jensen.dk/public/lenstest/17mm35.jpg (big file, not resized)
http://photo.klein-jensen.dk/public/lenstest/17mm35.cr2

Here are the same photo shot with my other lenses

http://photo.klein-jensen.dk/public/lenstest/28mm18.jpg (big file, not resized)
http://photo.klein-jensen.dk/public/lenstest/28mm18.cr2

http://photo.klein-jensen.dk/public/lenstest/50mm14.jpg (big file, not resized)
http://photo.klein-jensen.dk/public/lenstest/50mm14.cr2

http://photo.klein-jensen.dk/public/lenstest/85mm18.jpg (big file, not resized)
http://photo.klein-jensen.dk/public/lenstest/86mm18.cr2

[Tom W]

I'm not Drisley (really, I'm not! :) ), but I'd say that in the above test, the lens is backfocusing. I would test it again under better light though. It could be that the f/3.5 lens is struggling a bit with the lower light, whereas the faster lenses that you've tested are OK with it.

[tommykjensen]

Took a few more test photos in better lights (shutter speeds between 1000 & 2500) but I can't tell on these photos if there is a backfocus issue or not.

http://photo.klein-jensen.dk/public/lenstest/17mm35_1.jpg (big file, not resized)
http://photo.klein-jensen.dk/public/lenstest/17mm35_2.jpg (big file, not resized)
http://photo.klein-jensen.dk/public/lenstest/17mm35_3.jpg (big file, not resized)

[Tom W]

Depends on what you're focusing on. It's hard tell, you're right. The farther away you get, the bigger the depth-of-field.

[tommykjensen]

Depends on what you're focusing on. It's hard tell, you're right. The farther away you get, the bigger the depth-of-field.

I used center focus and did not recompose.

[Tom W]

I used center focus and did not recompose.

They look like the focus is good in the second set of shots, though it is difficult to really tell since the DOF is pretty big. If you could duplicate the other test, but with more light, it would make a valid test, at least for closer objects. Towards infinity may be considerably different.