Getting focus right is the most important thing

I migrated from semi pro DSLs with smaller sensors to the D750 and now I'm having to deal with 'real photography'. Depth of field was never something I worried too much about until now. I think this is the big pitfall for beginners and migrators moving to full frame. I can make mistakes with exposure but stand a chance of pulling them back in post. But bad focus is never correctable.

I have 50mm, 85mm fixed lenses and a 22-120 zoom. I put a DOF calculator App on my phone and started playing with new shots, whilst going back and looking at some poor results. Oh do I wish the camera info would show the electronic focus distance. That focus dial on my lenses is so small and obscure to use or is it just me?

Here's my dilemma. If due to lowish light I open up the lens aperture, I'm seemingly stuck with very little DOF, in some cases down to several inches. The eyes may be sharply focused but the nose might not be! I have 2 choices, increase ASA and tolerate more noise or slow the shutter/get tripod. Now cheap handy cams with IS can do a decent job even down to 1/10th second hand held, but even trying hard, I can't risk shutter speeds slower than 1/50th on the two primes. The Nikon zoom with IS is better but heavier.

So how does everyone handle DOF with a full frame camera, because it's totally different to working with even the best reduced area sensor consumer cameras. I can now understand why compact cameras have their place for point and shoot - If auto focus works, everything sharp! I am asking myself when I can use a wide aperture lens and coming to a conclusion when I am further away from the subject and get more DOF. Some say DOF calculators are not always recommended, but I've found trying my common lens/aperture/distance settings quite revealing. Where I'm confused is Auto focus picks a point on the subject and perhaps you want the to use more of the DOF in front, e.g you want head and shoulders sharp as well as outstretched hands. How can you change what Auto focus does or get around this? I've given up trying to get accuracy from the focus ring marks and realized critical focus has to come from the camera, or trial and error using the in camera preview zoom.

Push comes to shove, I bracket the focus.

If you think going from a crop sensor to a full frame is difficult, imagine shooting medium format... where 100mm is a 'standard' lens. Or large format, such as 8x10.... 'normal' is 300mm!

It depends what I shoot but when portraits I more often than not shoot as wide open as the lens allows and don't bother with the DoF. I try to make sure the eye(s) is in focus and the rest is what it is.

If I really need the DoF but can't lower shutter I usually take a step back and slightly crop the shot.

Also keep in mind that you can easily underexpose the D750 up to some 3 stops and correct it in post. That gives you some working room for DoF.

With the high ISO performance of the D750 I wouldn't worry too much about bumping it up so you can increase the DOF. Consider backing away from your subject as the closer you are the less DOF at a given f stop. Just my $0.02.

wtlwdwgn said:

With the high ISO performance of the D750 I wouldn't worry too much about bumping it up so you can increase the DOF. Consider backing away from your subject as the closer you are the less DOF at a given f stop. Just my $0.02.

Click to expand...

Thanks that's the way I'm going. Take a stock party shot of your friends sat around a table. The camera phones and my Canon Powershot with IS snap away and get their shots in perfect focus with plenty of DOF due to their small sensors. I have sufficient natural light from tungsten to open the lens, bump the ISO to 400 and get really nice soft lit natural pics with a good histogram but without the flash glare. Wrong, because I'm restricted by walls in the room and my subjects distances are from 4-12 feet. As much as I dislike flash, I can use it, drop the ISO to 200 and stop down to f11-f16 getting all my subjects in reasonable focus.

The D750 EXIF does include the DOF on shots, but I don't know why the focus distance isn't there and there is nothing in the info screen I've discovered yet. That data isn't usually shown in most photo editors, I found a DOS based EXIF reader that churned out loads of camera settings not normally shown. It looks as though all the D750 camera presets are saved with your pictures. My wish is for Nikon to pay less attention to the on screen focus zone boxes but show a rectangle or just 3 dots which change their shape or separation for each lens and aperture setting representing the focus point, near and far focus according to your choice of COC value. The central point zone is already there and they only need to calculate the near and far in focus points. My AF lenses seem to have a reduced focusing arc leaving insufficient space to engrave useful distance marks and DOF f stops. If the camera is setting focus electronically, tracks and works then that's fine, but I think it needs to translate the limited focus ring movement to a range distance you can see when shooting.