Depth of Field Demonstration

[Fitz]

What follows is a series of photographs to demonstrate the effect of aperture (f-stop) on depth of field, i.e., the area in which the image is sharp.

All the photos have been taken with the point of focus being on the rebel pilot in red in the middle, and with automatic exposure. They start with an aperture of f-36, the smallest aperture my Nikon DSLR is presently capable of, and run through in standard aperture steps to f-5.3, the largest aperture I can manage with this lens. The camera will actually handle intermediate aperture steps as well, but for demonstration purposes these eight images will be sufficient.

• Note: the photos were taken using a multi-area focusing system, and strictly speaking I should have used spot metering, centered precisely on the Red Dude. However, these will have to do as I am too lazy to repeat it all.

The miniatures are WotC Star Wars pre-paints, and are staggered at one inch (25mm) intervals. The camera's focal plane (i.e. the image sensor) was about 750mm from the focal point (i.e. the guy in red).

• The images are 1000px wide — you may have to open them in a new tab to get the full glory of a full-size photo. Or else you could just look at them on my blog at http://mojobob.blogspot.com/2023/03/depth-of-field-demonstration.html

[Spinal Tap]

Really useful, thanks a lot.

[fred]

Thanks for taking the time to do this.

I must admit I’m surprised just how much is still in the depth of field on the smaller f stop numbers. Perhaps it is because you have the camera a decent distance (75cm) from the figures.

[Fitz]

Yes, probably. With the resolution of digital cameras these days, even relatively cheap ones, you can generally afford to back off a ways and then later crop down the image to the relevant area. There's not usually much point in putting a photo more than about 800-1000 pixels wide online, and if your camera spits out images 5000 pixels wide, that gives you quite a lot of latitude.

Generally speaking, I'll usually only fill about a third of the image frame with Useful Stuff, and then crop and resize down to 800-1000 pixels wide.

[fred]

Yes, shooting wider, then cropping works great for images used online. It does take a bit of getting used to when framing the shot, but as your results show it works well in practice.

It might be instructive to post one of the un-cropped images too?

[Fitz]

Unfortunately I've already deleted all the original photos. I seldom keep the raw images for reference shots like these as the file sizes are pretty huge.