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Discussion in 'Open Discussion' started by Bullfrog, Jan 19, 2010.
For anyone needing a helping hand figuring out DOF: http://www.dofmaster.com/dofjs.html
Thanks Bullfrog. Initially I thought "circle of confusion" was a witty euphemism. Then I searched it and found this link which helped me understand better what it really means: http://www.cambridgeincolour.com/tutorials/depth-of-field.htm The pictures make it all much easier for me to get it. It's also a rather handy way to see and understand depth of field. Especially for folks who are visual, as opposed to mathematical.
This was a great place to try some "what if" cases. I have thought for some time that sensor size fits into the DOF equation due to differing amounts of enlargement necessary. So I used full frame (Leica M9 - which I DO NOT own but would gladly accept), 50mm f2 10ft focus as my comparison - a total depth of field of 1.45 ft.
When I tried the G1 with 25mm (to get comparable field of view) f2 10 ft, it showed 2.96 ft total DOF. The G1 with 50mm f2 at 10 ft had a narrower DOF than the M9 with the same lens, only 0.72 ft. This must be due to the need to enlarge a G1 image more than a M9 image. Interesting to me was that the G1 with a 35mm f2 lens had about the same DOF as a M9 with a 50mm f2 lens.
This helps me pre-think lens choices a little bit. Very nice information, Bullfrog.
A couple of extreme practical examples
nothing special - but shows you the DOF effect at different f stops
D300 with old NAI Nikkor 55mm f1.2 ISO 1000 indoors
@ 1 foot at f1.2 there is no DOF
@ 2 foot at f16 the DOF is 6 inches
(I reckon that this lens will be impossible to focus on my G1 - I just wish the camera had a "focus confirm" for MF lens, (as Nikon DSLRs)
and a quick shot in the kitchen
By the way, to use the program, enter .015 as the coc for the m4/3 cameras.
Shooter, can't you just choose a Micro 4/3 camera from the list instead?
I think you may be pleasantly surprised, Bill. With static subjects, I find that the magnified view in my G1 gives me more accurate and precise manual focus than I got using the "focus confirm" arrows on a Nikon D700.
I know it is a bit off topic
I use focus confirm thru the VF - then switch to Live View for the final tweek and then mirror up for the shot
The version on my iPhone doesn't have the cameras listed...yet.
Vivek & Jono Slack suggested the .015.
Ah, I didn't realize there was an iPhone version. Had only seen the web site.
Yessir! This here digital photo world is the s*it.
It's a free download and is great to have in the iphoney.
I reckon you'll be gettin it in a few minutes....
Photoshop has a cool program for free also.
I want some brownie points for this....
Here's a thread worth hanging on to. Being the visual sort, I found this link, which I mentioned above to be very helpful, courtesy of Cambridgeincolour.com's tutorial on DOF: http://www.cambridgeincolour.com/tutorials/depth-of-field.htm
ipod touch version, thanks a bunch
GREAT FOR VIEW CAMERA STUFF TOO.
Thank you for bumping this BBW. I've been trying to figure out how distance and aperture affected DOF by just testing settings. Bokah is a really cool sounding concept for a beginner like me, but when you don't really understand it (like me) you wind up trying to use to large an aperture and lose focus in the picture.
Below is an example where I caught my girls acting silly. I had just gotten my Minolta 58mm 1.4 + adapter and took this at f2 at about 10', focusing on my oldest in the middle. When I got home and loaded the pics I noticed that, even though my younger girls were just a little in front of her, they were more out of focus. So . . . I spent a good deal of time later that night trying to test it with distance and settings. It was a frustrating process.
Thank you for bumping and linking these sites. By using the calculator I now see that I only had half a foot or so of focal range.
Here's the pic:
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Just FYI, the Wikipedia article on Circle of Confusion lists the CoC for the 4/3rds format as .015mm. And the DOFmaster app is quite cool.
Just in case anyone is interested....I have installed the program on my Windows mobile phone and have been using it to check with no problems...
am inclined to agree from tests so far
Could you tell me which one you are using on your windows phone