TEST: Carl Zeiss jena Tessar 50mm f/2.8 vs El Nikkor 80mm f/5.6

[Hornblende]

Intro:

 

The Carl Zeiss jena Tessar 50mm f/2.8 is a lens I really enjoy shooting with, despite its small aperture.

I shot several time in ultraviolet light with it, and I noticed it does not perform very well compared to the EL Nikkor 80mm f5.6

Here, I make a quick comparaison between the two using a pinhole, wich garantee a 100% UV transmission.

 

On the fly I also tested my Lifepixel UV/IR cut and an old russian Industar M39 lens from my rangefinder.

 

Methodology:

 

A pinhole in a piece of tin foil is placed in front of my Baader-U filter, which is mounted directly on my Canon 6D full spectrum using an M48-M42 adapter and a M42-EOS adapter.

A piece of white PTFE is placed behind the lens in order to evaluate the transmission.

White balance is done on the PTFE piece.

 

Since my PTFE is small, I made a montage from 3 pictures with the same ISO and same exposure time.

 

Results:

 

Left to right: UV/IR cut filter, El Nikkor, Carl Zeiss Jena, Industar.

 

First of all, we note that the EL-Nikkor has obviously the best transmission, followed by the old Industar lens wich is surprisingly not so bad.

The Carl Zeiss Jena lens in far behind with a bad UV transmission. No wonder I had difficulties to shot in UV with it. I calculated the lens require EV+2.5 more exposure than the EL-Nikkor.

 

The UV/IR cut filter is not really UV cut, I wonder why they call it this way.

[Andy Perrin]

This is an excellent test. I like your idea of using a pinhole to avoid the effects of another lens in the testing.

[Andrea B.]

Nice test, Martin! Very clever idea with the pinhole.

 

Let me ask one question. Were the exposure times the same in each of the images used to make the merged image? I would assume so, but it it wasn't stated.

[Cadmium]

Martin, Very cool test. Yes, the El-Nikkor 80mm (the old version with the silver/chrome base) is a very good UV transmitting lens.

I like your pinhole idea.

I believe the filter is probably made of Schott BG40 or perhaps BG38, I don't know the thickness.

Given that UV doesn't show up in visual photos very well because it is so overpowered by B/G/R and IR, BG glass works rather well for Visual shots, even some cameras such as a D70 have internal filter profiles just like BG40 or BG38, transmitting well into the UV, and a D90 internal filter transmits a good amount of UV also.

Generally, most people using BG for visual filters find BG40 or BG38 to balance the most natural.

My experience using my Nikon DX cameras is that generally BG38 or BG40 look more natural than Baader UV/IR-Cut which looks more more red than even BG38.

In most cases I see no UV pattern with BG visual filters.

S8612, a type of BG glass, is too blue, and I never us it for visual, although I have seen people use it for that.

It depends some on the camera, which type of glass will look the most natural for visual.

If you compared the cut filter you show to BG40 and/or BG38, they would look the same.

Do they call it a UV/IR-Cut filter? All I could find was 'Visual Bandpass'.

'Bandpass' is exactly what Schott calls GB40 and BG38.

[Hornblende]

Thanks all.

 

I was inspired by this topic by OlDoinyo.

 

Andrea, yes the three pictures were taken with the same settings. I made the correction in the first post.

 

Cadmium, here is the "UV/IR cut" transmission curve from Lifepixel's website: https://www.lifepixe...-cut-filter.jpg

Anyway, it works really well for when I want to take "normal' pictures :)

[Herman1705]

Nice test! Thanks for sharing. I'll repeat this test with my Tessar T 50mm f/2.8 and my Rodenstock Rogonar-S 50mm f/2.8 EL. Where the Tessar T takes 30 s for an exposure the Rogonar-S takes 5 s. So that is log(5/30)/log(0.5) = about 2.5 EV.

[Cadmium]

Cadmium, here is the "UV/IR cut" transmission curve from Lifepixel's website: https://www.lifepixe...-cut-filter.jpg

Anyway, it works really well for when I want to take "normal' pictures :)

 

Thanks Martin, I knew you posted that graph/link before, but I couldn't find it with their filter.

Yes, that is the green line on the graph below, and looks like BG38 @2mm, which is what I personally prefer for visual shots with my D7000 and D90.

It says they use Schott glass.

I am a little surprised it is not BG40 which seems to be more standard with a lot of people these days. They are very close actually, as long as it is not being used for UV stacking,

in which case BG40 or better yet S8612 should be used instead (at an appropriate thickness matching the U-glass type and thickness).

Like I said, it will depend on the camera.