Jump to content
UltravioletPhotography

El-Nikkor 80mm/5.6 tests


Andy Perrin

Recommended Posts

I also received my El-Nikkor 80mm/5.6 today!

 

Two test shots with a 330WB80 filter, mounted on the rear.

 

F8 1" ISO800 (F# is approximate, because I forgot to check)

post-94-0-63742600-1482183819.jpg

 

So, there is a pronounced "glow" or halo around the awning in this one below. I'm guessing I need a lens shade? Or is this effect caused by something else?

 

F16 3.2" ISO800

post-94-0-25642600-1482183878.jpg

Link to comment

ok.

Just checking because the first photo seems to have a bit of veiling glare in it also giving it somewhat less contrast than expected.

But nothing that wouldn't clean up a bit in the editor.

 

I'm not sure what halo you are seeing in the 2nd photo? I see some reflection in the sign above the awning.

 

Always a good idea to try some kind of lens shade tests. I tend to be lax about lens shades and that is not a good thing. Sometimes they work wonders.

 

How "shiny" are your filters?

 

These photos look good though. The EL-80 is a nice, useful lens. I like it for both landscape or close work.

 

If you have the 80 on a helicoid (which you must have done), then sometimes if the helicoid is extended too far there can be a bit of light leak. Just a heads up.

Link to comment
The filters are very shiny. I have it mounted behind the lens, between lens and sensor. I have the golden side facing the lens and the dark side facing the sensor. The observed "glow" around the awning decreases if I stop down the lens to ridiculous levels, and gets worse if I open up. That's why I suspect it's something to do with off-axis rays.
Link to comment

But why just the awning, I wonder? Is the awning at the exact angle to somehow reflect back into the lens? If you raised the camera and shot more downward onto the awning would this effect be lessened?

It's a little bit strange. "-)

 

Anyway, enjoy that EL-80 !!

 

 

Later: The sun is at a lower elevation this time of year also.

 

I went out with my Solartech today and got a measurement of 1.7 mW/cm2 as compared to the usual 4-5 mW/cm2 that I measure during high summer days. So we gots us less UV at worse-er angles. Foo !!!!

Link to comment
Klaus suggested that I might have two separate problems: hazing (in the case of the awning) and a major light leak along the top of the camera (bottom of the frame since real images are upside-down). He pointed out that the trash can shows the light leak in particular. You can see the sharp gradient. I have not confirmed the hazing yet, but it's on the list.
Link to comment
Yes, but I think the angles were significantly changed between those two. The first one has the camera almost horizontal, the second one was angled down, facing more toward the light coming in from the window. If the light leak is on the top then this is consistent.
Link to comment

Heh, so I feel foolish: I tried to reproduce the "leak" today, and the problem was that in the second photo, the window sill was in the shot! Eliminating the window sill from the composition helped:

 

F5.6 0.2" ISO800 (330WB80/NEX-7)

post-94-0-85695500-1482255372.jpg

 

On the other hand, the strange glow from the awning is still there. As is the loss of contrast near the top of the image generally. I tried wrapping the camera, lens, and adapter in aluminum foil with no result, but when I used the foil as a make-shift lens hood, I got results:

 

Nothing on the lens

F11 0.8" ISO800

post-94-0-19821600-1482255494.jpg

 

With foil hood:

F11 0.8" ISO800

post-94-0-03782000-1482255547.jpg

Link to comment

Well there ya go!! Mysteries almost all solved. Omit sill, add hood and much better results. Hey, don't feel foolish. We all do these things!

 

I've been trying to decide if the awning stripes are close enough together to cause any kind of "interference" thing. Dropbox me a raw if you are interested to see whether anything unusual can be discovered by looking at the awning shot in Raw Digger.

 

Also I was wondering if there is some kind of sensor bloom going on. A visible shot of the awning might be a good idea for comparison purposes. If a visible shot shows this "halo" or whatever it is, then that would tell us something. If vis shot does not exhibit this, then it must be some kind of UV fluor or reflectivitity phenom going on. Could it be that the white stripes are so reflective in UV that it scatters the UV a bit? Not sure I've phrased that well, but maybe you get my drift.

 

Added Later: Andy, do you have a non-shiny UV-pass filter? If so, then an awning shot using the non-shiny filter would be very interesting for comparison purposes. These shiny filters are tough to use.

Link to comment
Hard to take a visible shot because the front of that lens is some weird diameter that I don't have a step ring for. It may be some time before I hunt one down. I'm currently rear-mounting the filter with my handy poster putty.
Link to comment

...some weird diameter

So it is --> 34.5mm.

I had to special order a nice front stepper for the EL-80 from Portugal or somewhere.

Link to comment
  • 4 weeks later...

Okay, so I finally threw in the towel on my 80mm/5.6 EL-Nikkor and bought another one. The old one is too hazy. This new one seem to be in much better shape. Compare below to post 10 above. Note that I used a 2.5mm BG39/2mm UG11 stack rather than the 330WB80 on this one, and the exposure details are different. I may try to exactly duplicate the earlier shot sometime soon. Still, the results seem much improved. That canopy "glow" is gone, even with no lens hood.

 

F5.6 0.1" ISO1600

post-94-0-73026800-1484679962.jpg

Link to comment

I just bought a EL-Nikkor 80mm on EBAY, I hope It wont have any problems like your first one :/

I am considering converting my canon 6D into full spectrum rather than acquire a old nikon D40, but it will cost a lot more in conversion + multiple filters..

Link to comment

Horneblende, true, but the resulting setup will be more useful for various experiments.

 

Andy, are you saying that your old EL-80 had internal haze? And that was causing the flare? If so, did you take that lens apart and try to clean it?

 

Are you both making sure you have the OLD EL-80 and not the newer one? The new EL-80 has the aperture window which leaks light.

Link to comment
Both EL-80s are the old kind. They are all metal. Yes, my original one seems hazy. I didn't take the lens apart (indeed, I've never taken a lens apart before, and I don't know if all the aperture blades would fall out or something on me?). I guess now that I have a nice one I can try cleaning up the other one. Otherwise it will just sit around collecting (more) dust. My original EL-80 also had a dent in the front that would not allow me to screw in a filter. So I would have to fix that also. Frankly, it was a mess!
Link to comment

And so may not be worth the trouble to clean up. :lol:

 

Although useful for learning how to take a lens apart?

I had an aperture blade disaster once. Not pretty.

But if you pay attention while disassembling, you can usually avoid dealing with aperture blade mishaps. Enlarging lenses are often so simply constructed that it isn't a problem to take them apart and clean them up.

 

Haze is sometimes chemical and not removable. I don't know much about that kind of haze. Or how to remove it.

Link to comment
enricosavazzi

The front half of the lens screws off. If cleaning the innermost optical surface of the front subassembly does not help, you then need to take apart this subassembly to clean the two internal surfaces.

 

You can clean the most frontal optical surfaces of the rear subassembly through the aperture, after opening it fully.

 

I am not totally sure about the rear optical groups, but it is possible that they also unscrew from the rest of the lens (including aperture) and then can be separated in the same way.

 

You should not need to disassemble the iris, but sometimes the wrong thread unscrews and the blades fall out of the barrel.

 

FWIW, I once had a 50 mm f/2.8 El-Nikkor with a hazy internal surface that did not clean no matter what I tried. One inner optical surface looked sort of "etched" or finely "sanded".

Link to comment
  • 3 weeks later...

I haven't played with the hazed EL-Nikkor yet, but here are some shots with the good one.

 

(That's actually the courthouse steeple, not a church.)

 

1.75 mm S8612, F8 0.005" iso100

post-94-0-46398600-1486238903.jpg

 

2mm UG11, 1.75 mm S8612, F16 0.3" iso800

post-94-0-44580600-1486238969.jpg

Link to comment
  • 3 weeks later...

I made a little "flare" test with my EL Nikkor 80mm.

 

Here is the procedure : I mounted the lens on extension rings in order to match the FDD of the lens (70mm). Then, I pointed the lens in the general direction of a bright light source (but not directly at) in order to see what happens. The apperture is set to f/11.

 

post-136-0-83476000-1487712192.jpg

 

Here are the results:

 

We see that the lamp creats "ghosts" in the lens and a reflection in the extension rings. These effects start to appear when the lens is pointed at 50° to the light source!

post-136-0-64471100-1487712193.jpg

 

If I point the lens even closer to the light source these effects are worsened.

post-136-0-73809100-1487712194.jpg

 

These artifacts are bright enough to get recorded by the sensor, this could explain the hazy look of some pictures taken with this lens.

Opening the apperture make things even worse.

The only solution I found to get ride of the ghosts and reflection is to use a long and narrow lens hood.

Applying black velvet in the inside of the extension rings/helicoïde could be a good idea too.

Link to comment

Thanks for the flare test, Martin. That was a good idea to test the lens while off the camera. Helps to immediately see the potential problems.

 

Lens hoods are the key! They help prevent flare, reflection rings and other light artificacts in any wavelength. I say this to remind myself not to be so lazy about using them. :lol:

Link to comment

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
×
×
  • Create New...