maybe post the original images and tell us what is the focus distance for each so we can look at more. I'm thinking the two lenses have different contrast.
Yes, something happens. You have a constant F/no zoom...!
Same distance, same F/no
50/2.8 > 18mm real aperture.
135/2.8 > 48mm real aperture.
As you've scaled the images from both 50 and 135mm to same size, of course the difference 18 to 48mm will be visible...
If you want a magnified part of the 50mm picture to look the same as the 135mm picture you would need 135/50=2.7 times bigger F/no to match them. That's the 50 @ F/2.8 and 135 @ F/(2.8*2.7) = F/7.6.
Then your "morph" example would match up with very little difference except for the slightly different bokeh character, SIZE of blur would match precisely.
Oh, that's right! Of course! I'm so slow sometimes.
Thanks theSuede. In a constant-aperture lens, like my 50-135, the iris becomes physically larger to maintain F2.8 as you zoom in. The larger opening at 135mm is what is causing the bokeh to get visibly thicker. I knew that the aperture did this in these kinds of lenses, but my brain didn't make the connection. Geez. Well, that answers it. Thank you.
So anyway, back to my lens choices.....
I guess the Vivitar 85mm F1.4 looks pretty tasty (for the price), eh?
I want to see some 100% crop samples from it at F1.4. That's the only aperture I'd use with it, so I want to know exactly what I will be getting.
