EMWL angle relay lens question!

[Jordi Chias]

Hi all!

 

I am a EMWL user since 2022 and I am extremely happy with it... I've been using the the 130º and the 100º lenses with the straight relay lens in Canon cameras and I think the performance of the lens is very good opening a bunch of new possibilities... At the beginning I did some tests about using the lens with or without the intermediate relay lens and I decided not to use this in order to get the best possible quality... IMHO there is a slight advantage on quality if that intermediate lens is not used. I use a monitor turn side up the image and compose.

 

Three months ago a friend of mine bought the EMWL angled relay lens. When he came back from a trip to Indonesia he told me that the he was experiencing a lack of quality, mostly in the sides of the image, with this angled relay. He sent me some photos and he was right. We asked Nauticam and they said that this lens is not easy to use and maybe we were doing something wrong.

I asked my friend to let me try his EMWL angle relay lens and after many tests I am not able to get the same quality that I get with my combo (focus unit+ 130º objective). I have tested the lens with #focus unit 2 and #focus unit 3 (as recommended in the port chart), with Canon EF 100mm+ adaptor and Canon RF 100mm and I have taken many pictures at different f/stops, from F16 to F32.

I even asked another friend to lend me his angled EMWL relay lens in order to compare between two different units. Both perform similar... What I see is that there is a loss of quality, mostly in the side of the images (softness and cromatic aberrations) and when compared to the straight relay lens the results are noticeably worst.

I have found some posts online that talk about backfocus problems, so I decided to focus manually, so I first magnify the focus point to check if it sharp enough and after that I take the picture (I use a tripod to improve consistency of my test).

 

I want to do some more test this week and I'd be able post some images to illustrate what I say but before that, I wanted to know if someone has used this angled relay lens and can give some feedback or advice. I am not sure if I am doing something wrong....

 

Thanks in advance for your help

Edited October 23 by Jordi Chias

[Isaac Szabo]

In my testing I also found that the relay lens reduced image quality a little, so I too went with a monitor instead. To me it makes perfect sense that adding in a lens with 14 additional elements whose only purpose is to invert the image can only have a negative impact on image quality. Nothing in optics is perfect, and I think there are bound to be slight errors that accumulate with so many elements. 

 

I have not tried the angled relay, but I am not at all surprised if it degrades the image a little more than the straight relay. After all, it is manipulating the image to an even larger extent, and again, not in an effort to improve image quality. So I personally trust your results. 

 

If you do more testing, I would recommend starting at f/8 instead of f/16. Peak sharpness in my testing was around f/8-f/11, and by f/16 I noticed a significant reduction in the sharpness of fine details due to diffraction. So image quality comparisons done in the f/8-f/11 range will likely give clearer results than those done at f/16 and above. That said, obviously for real world shots you may sometimes value the extra depth of field over peak sharpness.