Shooting photos at really small aperture

Awais Yaqub · May 26, 2009

Hello people i was wondering if it is alright to shoot landscapes at apertures like F22, F18 etc?, without significant loss of sharpness.

I am huge admirer of photographers at Timecatcher.com they have used 17-40L on crop and FF bodies and used really small apertures example.
Considering their professionalism don't you think they should worry more about diffraction ?

:scratch

ziggy53 · May 26, 2009

Awais,

According to "The-Digital-Picture.com" the Canon 400D/XTi is diffraction limited at f9.3. This means that any lens used beyond f9.3 will limit resolution on that camera.

If, for instance, you shoot at f12 your available resolution will be at about 6 megapxels equivalent. If your image only requires 6 megapixels of resolution, or if the subject matter will benefit from extended DOF more than it will benefit from resolution, then the smaller aperture may sill be desireable.

I suggest aperture bracketing if there a question about which to use and if there is time for more than one exposure.

BTW, the Canon 5D is diffraction limited at about f13 and the 5D MKII/1Ds MKIII are limited at around f10.

A larger image format allows a smaller f-stop before diffraction limit, but, because of the difference in focal lengths and prespectives involved, a smaller f-stop is required in larger formats to produce the same DOF as a larger f-stop in the smaller crop formats

Griffin · May 26, 2009

Thanks! I learned something. Now I know why you wouldn't want to just throw the aperture all the way down.

So, you need to take into account the DLA (Diffraction Limiting Aperture) and the lens "sweet spot" when searching for the best possible sharpness for pixel peeping.

Cameron · May 26, 2009

What Ziggy and Griffin say is true - beyond a certain point you will experience some negative effects due to diffraction, however, that's only one piece of the equation. In the image you linked I suspect the goal was to get a longer shutter speed to get the feel of the motion in the water (1.5sec exposure). With a wide-angle FOV in that shot the DOF would have been great at half the aperture; I suspect that depth-of-field was not the reason for using f/22. Was the resolution slightly compromised by setting it at f/22? Sure. Does it make a tangible difference in the final print? Maybe not. It sure looks sharp to me.

Without the use of a neutral density filter or stopping down to f/22, however, there's not way he could have achieved that same look - it was too bright. Sometimes you make small sacrifices in absolute quality to get the shot.

ziggy53 · May 26, 2009

Griffin wrote:

... So, you need to take into account the DLA (Diffraction Limiting Aperture) and the lens "sweet spot" when searching for the best possible sharpness for pixel peeping.

Pixel Peeping is rarely the best criteria for building an image. Ultimate center sharpness vs edge sharpness rarely coincide at the same aperture, so almost everything is a compromise. It's important to keep every shooting option in perspective and under control.

Tee Why · May 26, 2009

Stopping down beyond a certain point will result in diffraction, especially around f22. However, IMO, as long as the image is sharp enough not to distract, that's all one needs.

If stopping down a lot at the cost of sharpness to get more dof or to slow down motion adds to the overall look of the shot, then it's all right with me.

The sharpest picture with poor composition or execution is not a good shot in my view. I'll take a soft shot with great lighting, timing, and exposure any day.

BeaKeR · May 27, 2009

ziggy53 wrote:

According to "The-Digital-Picture.com" the Canon 400D/XTi is diffraction limited at f9.3. This means that any lens used beyond f9.3 will limit resolution on that camera.

So according to that, if I picked up that ridiculous 1200mm tele lens and stuck it on an XTi, it would be diffraction limited at f9.3? With an aperture 129mm across?

I must be misunderstanding something about diffraction here, because I thought it was inversely proportional to the size of the aperture.

I poked around the site you mentioned a bit, but couldn't find much explanation of what that figure means. Do you have any idea?

HenryPeach · May 27, 2009

It's easy enough to make large prints, and see where or if aperture diffraction becomes a problem. My experience is that many of the concerns worried about in internet photo forums don't appear as readily in the real world. I'm not trying to say diffraction isn't worth worrying about; I'm just saying that you'll get more valuable information from some personal test prints.

I've noticed that photogs worry about all sorts of things these days that were rarely of concern before everyone was pixel peeping. All sorts of stuff you can see on the computer screen will never show up in even the largest prints.

And instead of worrying about sweet spots make some test prints from your lenses at max aperture. When they come back looking great you can stop limiting yourself based on photo-geek anecdotes, and start fully using the tools with the all the options they allow.

pathfinder · May 27, 2009

HenryPeach wrote:

It's easy enough to make large prints, and see where or if aperture diffraction becomes a problem. My experience is that many of the concerns worried about in internet photo forums don't appear as readily in the real world. I'm not trying to say diffraction isn't worth worrying about; I'm just saying that you'll get more valuable information from some personal test prints.

I've noticed that photogs worry about all sorts of things these days that were rarely of concern before everyone was pixel peeping. All sorts of stuff you can see on the computer screen will never show up in even the largest prints.

And instead of worrying about sweet spots make some test prints from your lenses at max aperture. When they come back looking great you can stop limiting yourself based on photo-geek anecdotes, and start fully using the tools with the all the options they allow.

Henry, you know these are incendiary comments, don't you??

Awais Yaqub · May 28, 2009

Thanks for great information !

I have made print of 24x20 shot with 17-85 at F32 and it is amazing !

But when i start reading articles online for sake of learning and knowledge i get confused. Diffraction and focusing at hyper focal distance are two terminologies i never understood but i am trying.

Thanks once again for great input
I

Shooting photos at really small aperture

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