what DOF for the 17-40?

[petiot]

Hi everybody. I am getting obsessed with the 17-40 L canon lens. So i dont think it will be long before i get one

Although i wonder what type of dof i can expect from this lens a 40mm at f4 with a 10D?. more exaclty i wonder if it is possible to nicely detach the subject from this bakground at such short focale and at f4 (and possibly at close range ~ 50 cm).

I am using a 24-85 and this lens provides a very usabel zoom range. I am a bit concerned about the lack of flexibility of the 17-40 zoom range. Anyone made the same step (form 24-85 to 17-40)before?

many thanks

Dan

[ssim]

I had the 24-85 and changed over to the 24-70/f2.8 L for this focal range. I also acquired the 16-35/f2.8 L lens for the wider focal plane.

To exchange the 24-85 across to a 17-40 I think that you will find you will miss the 41-85 range. You will probably see a deeper DOF with this lens but this all depends upon how close you are to your subject at f/4.o.

To be quite honest, I use the 24-70 alot more than I do the 16-35.

[Jesper]

The Canon Camera Museum has depth-of-field tables for many Canon lenses. Here is the Lenses section: http://www.canon.com/camera-museum/camera/lens/f_lens.html

Lookup the EF 17-40 f/4L. At the bottom right of the info page (you'll need to scroll down) is a link "Depth-of-Field Data", which will give you a table with the DOF at different aperture and zoom settings.

[jyrgen]

Since you use 10D, you probably get better values with DOF calculator (http://dfleming.ameranet.com/dofjs.html).

[petiot]

Hi all
Thank you for your answers, all very usefull. As for ssim, beleive me i would like to buy a 24-70 L lens but i can t afford it.

The DOF calculator is very usefull (never found this one). it gives me a good idea of what to expect. thank you all.

Dan