DOF confusion on a crop sensor camera

[Siv]

Originally Posted by ldelacruz

Siv,
Is your question for educational purposes only or are you researching to buy a new camera?

Lonnie, I'm always thinking about buying more toys! To be honest I haven't reached the limit of my XTi but the wife and I fight over it so a second camera is probably on the cards, especially if we manage to go on safari this summer. I was seriously thinking of getting a 7D but now I'm not so sure.

The question was also somewhat academic since I wanted to better understand the DOF difference in user experience (i.e. subject framing) between a FF and crop for a given lens since the number of lenses I have is a limit.

Where I suffer is in shooting my kids - they are fast and I often cannot get the distance I need from them to get good separation from the background. Also, most of the shooting is indoors so I need something that works well in low light. I think my ideal camera would be a 5D but with the focusing speed of the 7D - not something that exists yet (I can't afford a 1D) so I'm now not really thinking about buying either.

I also take lots of photos of "things" like pens and watches and for these, my XTi is more than enough.

[ronocnikral]

sell the breitling, get a 1d.

[crazeazn]

anybody have the time to test this out?

setup a FF, 1.3, and 1.6 all with the same lense (how about a 35 or 50)

then crop the FF and 1.3 to achieve the same field of view as the 1.6

then lets compare the background blur, bokeh, etc. al


just to be that person, i think the pixel density is important and wasnt discussed.

[scottbuckel]

John - It is interesting if you read the literature about DoF you can find out that the math actually does not discuss the blur and degrees of blur - and for a pleasing photo as you suggest these are actually quite important, but can not be quantified. Some of us like the blurs of Nikons better than Canon, while other think Ziess glass is the best all around and we will never get everyone to agree.

Also in my explanations keeping the same framing would have required one to move the camera either closer or further away to keep the pixel density constant and this is one of the reasons I kept wanting to hold the framing of the image constant.

I did find one observation quite interesting, in many of the statements, people want to stand in the same spot and not move and then crop the image. I wonder why?

Siv - that is a cool looking watch. For me there are two possible reasons for moving to a FX sensor - you do selective focus work and want less DoF for those dreaming soft focus images or you really like using wide angle lenses. I guess there would be third reason - they are cool and I want one.

Scott

[Siv]

Originally Posted by scottbuckel

Siv - that is a cool looking watch. For me there are two possible reasons for moving to a FX sensor - you do selective focus work and want less DoF for those dreaming soft focus images or you really like using wide angle lenses. I guess there would be third reason - they are cool and I want one.

I have the 17-55 at the moment and 17mm almost not wide enough for me. I'm often cutting feet off the kids and they're not that big.

And yes, it's cool and I want one ;)

[ldelacruz]

Originally Posted by Siv

Lonnie, I'm always thinking about buying more toys! To be honest I haven't reached the limit of my XTi but the wife and I fight over it so a second camera is probably on the cards, especially if we manage to go on safari this summer. I was seriously thinking of getting a 7D but now I'm not so sure.

The question was also somewhat academic since I wanted to better understand the DOF difference in user experience (i.e. subject framing) between a FF and crop for a given lens since the number of lenses I have is a limit.

Where I suffer is in shooting my kids - they are fast and I often cannot get the distance I need from them to get good separation from the background. Also, most of the shooting is indoors so I need something that works well in low light. I think my ideal camera would be a 5D but with the focusing speed of the 7D - not something that exists yet (I can't afford a 1D) so I'm now not really thinking about buying either.

I also take lots of photos of "things" like pens and watches and for these, my XTi is more than enough.

It is hard to do that with 1 camera. It takes me 2 cameras to pull that off. 5D MKII for low light and portraits and 1D MKIII for sports and wildlife. Pick your most important type of photography and build from there. If I were you it would be the 5D MKII.

[venchka]

Just go shoot folks.