Resolution Chart/Targets

[Grif]

Any way to get a reasonable resolution chart to check out a lens at say 1 and 10 meters without spending a pile of money? I wouldn't mind spending $30 or so, but I'm not in need of a really hi dollar one. Vertical and horizontal lines, circles, line pairs. Mostly a basic overview of lens behavior?

I think I've still got enough stuff to build one good enough by hand from the drafting days if I really need to. The resolution side would likely not get done if I need to DIY it.

[ic-racer]

I think there are some on the internet you can download and print out. Search for USAF test chart. http://medfmt.8k.com/mf/USAF.pdf

[Nicholas Lindan]

http://accurateshooter.net/targets/usaf1951.pdf - about 1/2 way down

[Photo Engineer]

I think there are some on the internet you can download and print out. Search for USAF test chart. http://medfmt.8k.com/mf/USAF.pdf

This site is restricted!

PE

[willrea]

This site is restricted!

PE

Copying and pasting the link or just refreshing the page after you get the error gets you to the file fine.

[Grif]

Ok,,, Now I"ve got the same resolution target I used to use in the microfilm lab in the very early 70's. Now for something with some straight lines and corners?

[ic-racer]

This site is restricted!

PE

Oops, how about this one: http://szedo.extra.hu/USAF1951.pdf

[Photo Engineer]

Well, the original site does not work even with refresh. Copy and paste works to give the same chart in all references here.

The thing that I did not post until I could see them all is the fact that these are all one "polarity". You must have a negative and a positive set of these to run a test on both image "bloom" and image "fill in". You can only do this with 2 charts. I have both of these in 4x5 and 35mm versions. I find them very useful. The charts in 35mm size are available from Edmund Scientific but are quite pricey.

BTW, most charts like this are intended for contact printing rather than being photographed using a camera, but a large size version of the charts in your references can be used to determine some level of sharpness. However, to do it accurately, you need a set exposed in-camera and a set exposed from the originals directly onto the print material so that you can compare them. In such a test you would then have 4 final prints.

PE

[Q.G.]

Bloom and fill in are the same thing: spread.
So a negative version will not be able to reveal anything a positive version would not show already.

Charts like this are indeed intended to be photographed using a lens. You already have a comparison for your lens test in the chart itself.
But unless you are examining the aerial image produced by the lens, you will indeed be testing the emulsion of the film too. If you print the negative before examining, you'll be testing the emulsion of the print as well. Plus the loss created in the transferral from negative to print (whether it be by contact or projection).

These charts therefore are of very limited practical use, unless you put the microsope on the optical bench to examine the aerial image produced by the lens.

[Nicholas Lindan]

I don't have many pictures where I look at it and wince, thinking the lens really screwed that one up.

* * *

When I test I read the resolution target results by examining the print. I am only interested in what can be produced in a print I can hang on the wall.

Separating the resolutions of the lenses, film and paper is interesting for lens, film and paper designers but not of much practical use for a photographer.

When looked at as a system the resolution of the camera lens isn't really all that important. Using Tech Pan, a tripod, a critical magnifier, bracketing the focus, using the lens' optimum aperture, and doing all the rest one can do, I find a really good lens - a Sumicron or Micro Nikkor - can produce a usable 80 lp/mm on a print. A $100 consumer zoom can't do much better than 60. Without looking at the prints with a microscope it is hard to see much difference between the two lenses.

Shooting hand held, wide open, at medium/low shutter speeds, on high speed film or using an 'acutance developer' degrades the system performance to such an extent that lens performance is largely irrelevant. Which is as it should be - it's the subject matter that makes the picture significant, not the lens.