I can see CA without taking a picture...is that bad? :P

prodigy2k7 · Aug 14, 2008

I have a screw on macro/wide angle lens that I dont use anymore...I unscrewed it (its 2 pieces screwed together) and its shaped liked this () and its kinda thin...anyways it basically macro...only extreme close up is in focus...also very shallow DoF... So ya im holding this piece with my hand looking through it at my finger...and I can see my finger print all magnified a little....and I can see some CA on the borders of my finger...its kidna interesting....

Garbz · Aug 14, 2008

Two things. Firstly looking through a lens is not the same thing as taking a photo through a lens (because our eyes have ANOTHER) lens before our own sensors.
Second. Anytime you look through a lens, even in a viewfinder, the aperture is wide open. By far the worse conditions for CA unless you have some ludicrously expensive fully open corrected lens like the Noct-Nikkor AI-S 58mm f/1.2 ASP or something. The photo you take is often stopped down slightly and will be sharper and have less CA.

prodigy2k7 · Aug 15, 2008

lol ok mr. technical!!!

I was more or less playing around... no real point intended by this discussion...just some fun

Garbz · Aug 15, 2008

Wait a sec!!!!!

Two pieces like this () screwed together, and you looked through it. I have one of those:

Sarcasm aside a friend of mine actually used one separating the two elements a bit mounted it in a tube and put a Canon EF mount on the back. Yes CA was NASTY.

Bifurcator · Aug 15, 2008

If you take that magnifying glass and hold it up to something like a bare fluorescent bulb you can indeed see the CA (dispersion) around the edges of the lights.

I also have a lens made out of the threads from a rubber hood, a camping propane can with the top and bottom cut off, and a magnifying glass lens. It's not aspherical so you really need to mask out the outer 1/3ø in order to kill the worst of the dispersion.