Chromatic Aberration with Cooke 18-100

[Andreas Mendritzki]

So we've been toying with the idea of picking up a Cooke 18-100. . .

Its been a while since I've shot with one, but we recently had an old 20-100 in. I really like the look of these old zooms, but one thing that jumped out at me with the 20-100 that I didn't recall noticing so much with the 18-100 was the chromatic aberration. I wish I had grabbed a frame to post, but man oh man, it was intense. With a rim light falling on to some objects on a desk, we had a massive magenta outline. It was so intense it looked like it was some kind of focus assist that was turned on! And when we racked the focal plane forward the CA turned a nice bright green. It was so incredibly intense.

I'm wondering, is this something that is generally less pronounced with the 18-100? Was this perhaps especially bad with this particular lens, or are the 20-100's known for this?

thanks!

 

[Jeff Kilgroe]

It's better on the 18-100, but there is still a a significant amount of CA compared to most modern lens designs. The 18-100 is still a fantastic lens though.

 

[Andreas Mendritzki]

Thanks Jeff.

That's pretty much what I remembered. I just started to doubt when I saw how much I was getting with the 20-100.

 

[Mick van Rossum NSC]

Just not really sure if it is CA what you see, or a phenomenon that I've seen a couple of times on red material, a strong highlight/rim light that turns into a straight pink/magenta, especially with a dark background. CA has in my opinion 2 colors (complementary) , is far more subtle and not very sharp like this effect . Again, not sure since I have not seen a frame grab, but can remember some 3 year old discussions about it with Deanan and Graeme. Then again CA in Cooke lenses is a known issue, I've seen it in S4's and I have it on my 25-250 Mk2.