D800 is within factory standard! Needs +20 to stop it front focusing.

Started Feb 20, 2013 | Discussions thread
digital ed
Senior MemberPosts: 2,998Gear list
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Re: Mike, Robin, anyone else for that matter
In reply to John M Roberts, Feb 21, 2013

John M Roberts wrote:

michaeladawson wrote:

Robin Casady wrote:

digital ed wrote:

Robin Casady wrote:

digital ed wrote:

Assume LV manual focus gives best focus for Cam/Lens/FL/Aper/Illum.

YMMV, but I wouldn't trust LV manual focus. I find that it is not as accurate as one could hope. I think it better to take a shot and enlarge it in playback (or Lightroom tethered). Delete the image if it isn't right and try again. Tedious, but because of the poor quality of LV, I think it would be more reliable for critical focus.

BTW, I find LV CDAF to be less reliable than PDAF on my D800E.

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Robin Casady
http://www.robincasady.com/Photo/index.html
"The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts."
— Bertrand Russell

What can give the photographer a better example of the optimum focus than focus on the sensor itself.

Having a better quality Live View. With line-skipping and noise (especially in low light) I find LV on the camera LCD to be less than ideal. I've done a number of shots where PDAF produced a better focus than I could manually focus in LV with medium magnification (full magnification being beyond 100% and often unusable).

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Robin Casady
http://www.robincasady.com/Photo/index.html
"The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts."
— Bertrand Russell

I can attest to your experience Robin. I have been through my share of AF point testing with my D800 in futile attempts to satisfy my fear that I could have a body with an issue. For the record, I don't believe I have a problem body. But that doesn't keep me from testing from time to time

Anyway, to the point... During all this testing I often find that the PDAF image is sharper than the CDAF image from LV. And in my experience it happens with both AF and manual focus when in Live View. Not a lot... just often enough to keep those seeds of doubt in my brain.

I have not yet been comfortable trusting my eyes with LV manual focus. I hear and read a lot that to obtain the best results, use LV. If I have time, which I usually do with much of my subject matter I will use my method used for 40 years, through the viewfinder manual focus. This is more difficult with my DSLR's and especially at infinity where detail is so small. Sometimes I do find this faster then to rely on the camera to determine what exact area I am wanting in focus.

Now days are we able to trust the VF when it appears to be in focus? With my cameras it seems so but that may be an isolated sampling. In what mechanical conditions can the FV show sharpness yet the sensor plane may not and to what level of concern can this actually be?

Thanks,

John R

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Mike Dawson

Sometimes I think people do not have adequate reading comprehension.

Referring to my post(s). My point is that manual focus evaluation on the sensor is the best that can be done, no mirrors or focus sensors to be adjusted or mis-adjusted. If you do not trust what your eyes see on the LV LCD screen then take several pictures from LV using manual focus and choose the best focused picture using playback in your computer to choose as the reference. I have done this and do not find any significant variation. There are tethering programs that allow LV to be displayed on your computer live while focusing also getting around the LV LCD display situation.

Once this is done, taking pictures in PDAF mode while adjusting the AF Fine Tune allows comparison to the reference photo of the different AF Fine Tune settings to achieve the best and centered AF Fine Tune adjustment point. Evaluation can easily be done using the camera tethered to the computer in LR4. Zoom in on the target photos on the computer in LR4 to choose the optimum.

In no way am I saying shooting manual focus in LV for normal picture taking is the best way if you cannot adequately see the image in LV LCD zoom.

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