DPReview.com is closing April 10th - Find out more

Do you prefer using low, mid, or high apertures for focus stacking?

Started Mar 14, 2018 | Polls thread
Bill Janes Senior Member • Posts: 2,042
Re: Do you prefer using low, mid, or high apertures for focus stacking?

beginner_macro wrote:

I prefer using F/8 for FSing because there won't be any diffraction. But that's only for still subjects; for more jumpy subjects I use F/11 so that if they jump/fly away I have photos with a larger DOF.

With sharper lenses like the Canon 100mm F2.8L, you can go all the way up to F/18 without obvious diffraction. So, for FSing, I'm trying to get the best DOF without introducing diffraction - for me that means F/8 to F/11.

Your analysis is incorrect. Diffraction takes place at all apertures and limits resolution. The diffraction limits are shown below for green light.

These figures are for optical resolution. System resolution includes sensor resolution and the system resolution in terms of MTF is the product of these resolutions. The system resolutions for the 100 f/2.8 L at various apertures on a 24 MP full frame camera have been determined by Optical Limits.com and are shown below.

Maximum resolution in center of the frame is at f/4. Prior to this aperture, resolution is limited by lens aberrations. Beyond f/4 resolution is limited by diffraction and resolution is considerably lower at f/16. Sharpening, preferably by a deconvolution method, can restore some resolution but the image will not have the brilliance obtained with the optimum aperture.

-- hide signature --

Bill Janes

Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow