Balancing sharpness and depth of field (my crappy photo included)

Adroit

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As I understand, the sharpest f-stop is f/8 (which I know can vary slightly depending on the lens), but provides a shallower depth of field than f/10, f/16, and beyind f/16 your photo starts to lose sharpness due to diffraction. So with these facts, I have some questions:

-When you are photographing something that is relatively close (take for example my photo below), would it be better have a sharper image / shallower depth of field using f/8, or a less sharp image / wider depth of field at a higher aperture? For this photo specifically, I wanted to get everything in focus, but now I'm left wondering if I should have stopped up to get more detail for the front of the image.

-At what distance could you forgo depth of field altogether and just select the sharpest aperture? (As I understand, the further your subject is from your film/sensor, whether it be by physical distance or focal length, the greater depth of field you have)

Any thoughts and advice would be greatly appreciated. Thank you.
$DSC_0625.jpg
(Also please ignore how blurry this photo is: at the time of shooting, I was using Aperture-priority mode with Auto ISO. Once the maximum ISO of 1600 was reached, my D300 decided to lower the shutter speed to 1/30 at a 90mm focal length. So yeah... kinda blurry)
 
I myself would use a aperture of f/16, this photo is composed using the leading lines technique, you want the viewer to see the end of the photo because their eyes are leading their, If you have a wide aperture, the trail would be cut and then get blurry making the viewer disinterested as they are only looking in the middle.
 
When exactly the lens you're using is how sharp depends upon your lens. Many lenses already reach their maximum sharpness much earlier than f/8, and diffraction can kick in earlier than f/8, too.

For example check out the test of the Nikkor AF-S 35mm f/1.4 G at www.photozone.de: the lens has the maximal sharpness at f/4.0, the borders and edges get a bit sharper at f/5.6 while the center already declines, and from f/8 on sharpness drops again.
 
Yes, definitely do some research about your lens. Some lenses don't lose sharpness until at least f/11 and you could use f/16 without giving up a lot. You need to know the limitations of your equipment.

Oh, and don't use auto ISO. You need to be making that decision. I don't know your camera model, but it might be possible to set a higher ISO and use a little noise reduction and end up better off.
 
Yes, definitely do some research about your lens. Some lenses don't lose sharpness until at least f/11 and you could use f/16 without giving up a lot. You need to know the limitations of your equipment.
I didn't know that lenses could vary so greatly. Thanks, I'll check it out.

Oh, and don't use auto ISO. You need to be making that decision. I don't know your camera model, but it might be possible to set a higher ISO and use a little noise reduction and end up better off.

Really? My current method is shooting in manual so I have complete control over my aperture and shutter speed, set my default ISO to 100, and then let the camera's light meter decide which ISO to use. I only shoot up to 1600 with my D300; anything above that is too noisy my eyes. 1600 is slightly noisy, but Lightroom can bring it down pretty well. What is wrong with letting the camera choose the ISO?
 
Oh, and don't use auto ISO. You need to be making that decision. I don't know your camera model, but it might be possible to set a higher ISO and use a little noise reduction and end up better off.

Really? My current method is shooting in manual so I have complete control over my aperture and shutter speed, set my default ISO to 100, and then let the camera's light meter decide which ISO to use. I only shoot up to 1600 with my D300; anything above that is too noisy my eyes. 1600 is slightly noisy, but Lightroom can bring it down pretty well. What is wrong with letting the camera choose the ISO?

Originally you said you were shooting in aperture-priority, so then the camera would be choosing shutter speed and ISO. I suppose you could do this, but it seems better to me to have the camera only making one decision. I normally use aperture priority with manual ISO and if I don't like the shutter speed I get I decide whether to change aperture or ISO. However, if you are really using manual with auto ISO, this amounts to the same thing, so I don't see a problem with that, unless you end up taking shots at relatively high ISO where you need to use noise reduction, but you could have changed shutter speed or aperture instead.
 
Up until now I've been shooting Auto-ISO with Aperture priority, but after doing some photographic-soul searching over the past week, I realized the errors of my ways. But you nailed it - either way, your camera should only be making one decision for you. Thanks for your help!
 
As I understand, the sharpest f-stop is f/8

For your lens? Or in General? Typically F4 is sharpest unless you are using a wide angle then f8 might be the better choice.
 
Keep in mind that "sharpness" might not actually matter depending on how you're using the photo.

Your camera might capture 16, 20, or more megapixels. But when you post a photo to the web, the website might only use about 2 of those megapixels (or less!)

"Sharpness" is one of those catch-all phrases that tries to sum up a lot of other optical effects which are more readily isolated and measured. Usually when someone says "sharpness" they mean "contrast & resolution" (but there are other effects, CA for example, that might get grouped in.) Even diffraction limits don't show up in an image unless you're displaying it in a fairly large high-resolution size.

Unless you're planning to print very large images or cropping into a very tight area or otherwise display your images in very large sizes, just worry about the overall depth-of-field you need for your image and don't worry about which f-stop is precisely the "sharpest" f-stop for that particular lens or whether or not your camera will be diffraction limited.
 

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