Quick test cpn28/4 stacked vs lomo 3.7stacked vs MP-E

[Antal]

Hi,
I just did a quick comparison for my personal use, but maybe it is still usefull to someone:
-Componon 28/4 reversed, iris transformed by Robert O'toole, stacked on MakroSymmar fixed iris 120/5.6 mag ca 4X
-Lomo 3.7, stacked on MakroSymmar fixed iris 120/5.6 mag ca 3.6X-3.8X
-Canon MP-E 65mm at 5.6

The TL is sligthly beyond infinity, means the lens is nearer the sensor. Just because of adapters..
Camera is FF Canon 5D m4. Studio flash and Liveview. Stack 10 images with 6µ steps, sharpest image used.
Default sharpening in C1 (because this is the way I will use the lens in real life..)

At first test the CPN not tack sharp and not very contrasty. Closing the iris a little and some flocking in the frontelement with the white typo made huge difference.

The Lomo is warmer, more contrasty. Very sharp but degrading in the FF corner. Maybe some spacing btwin Lomo and TL would bring improvement in the corner. I can not test field curvature since my chip is to small and not perfectly perpendiculary to the optical axe.

CPN with special flocking and stopped down is very sharp, very good coverage, clean, but slithly less contrast dan the Lomo.

MP-E is just bad.
http://antalthoma.ch/downloads/lenses.png

Edit: Sorry for external image, but I don't get my file uploaded

[Bakwetu]

Where did you flock it, was it the inside of the detachable lens hood? I would like to use the hood but it is a bit long so it shadows the ligth I use when I use it stacked.

[RobertOToole]

Hi,
I just did a quick comparison for my personal use, but maybe it is still usefull to someone:
-Componon 28/4 reversed, iris transformed by Robert O'toole, stacked on MakroSymmar fixed iris 120/5.6 mag ca 4X
-Lomo 3.7, stacked on MakroSymmar fixed iris 120/5.6 mag ca 3.6X-3.8X
-Canon MP-E 65mm at 5.6

The TL is sligthly beyond infinity, means the lens is nearer the sensor. Just because of adapters..
Camera is FF Canon 5D m4. Studio flash and Liveview. Stack 10 images with 6µ steps, sharpest image used.
Default sharpening in C1 (because this is the way I will use the lens in real life..)

At first test the CPN not tack sharp and not very contrasty. Closing the iris a little and some flocking in the frontelement with the white typo made huge difference.

The Lomo is warmer, more contrasty. Very sharp but degrading in the FF corner. Maybe some spacing btwin Lomo and TL would bring improvement in the corner. I can not test field curvature since my chip is to small and not perfectly perpendiculary to the optical axe.

CPN with special flocking and stopped down is very sharp, very good coverage, clean, but slithly less contrast dan the Lomo.

MP-E is just bad.
http://antalthoma.ch/downloads/lenses.png

Edit: Sorry for external image, but I don't get my file uploaded

Hi Antal,

Good to know you are making progress with the new parts.

The Lomo 3,7 and CPN 4/28 are two of my favorite lenses or all time, and the MakroSymmar 120 one of the top lenses of all time!

Couple of notes:

Make sure all the tubes and adapters are 100% flocked. I once left one single short section of shiny tape, we call it scotch tape here in the US, and it created glare, a hot-spot, and it took me 20 minutes to figure that out.

Experiment with using a paper disk between the two lenses to stop down, sometimes this gives better results.

Some rear lenses increase contrast 1 stop down, to maybe f/8 or so, any farther usually causes corner shading.

I like to use a short piece of flocking material over the lens of the lens to shade the front element. But don't make this too long, or it can cut down on the working distance too much. I usually tape it in place. This can really give you nice deep blacks!

Don't forget to check for fingerprints on lens surfaces!

The CPN 4/28 is just a fantastic little lens. See this post, just in case you missed it: https://www.photomacrography.net/forum/ ... hp?t=41215

This 4/28 CPN was made in 1963 and the 100% crop results are great!



Best,

Robert