Some very basic lens test with ? dandelion

[ulf]

Science and technology is meant to be shared imho. Good gurus share.

 

You will always know everything I know even though it isn't much. B) (And I'm not a guru.)

 

 

 

The openness, helpfulness, sharing and mutual respect shown in this forum makes it my very favourite site on the net.

 

I really appreciate the way things work here.

I have not found anything similar anywhere else.

Your efforts running this site is a very important part of that.

Even if not being a guru I too try to share as much as possible.

 

Andrea, I just want to thank you for the opportunity to be a part of this great community.

[Andrea B.]

I'm so happy that we all together have created such a useful and friendly forum. Thank you to everyone who participates, stops by or just reads from afar. Let's keep the conversations going!

 

I do wish I had a bit more time to keep Stickies and Lists up-to-date. I'm still trying to work at my own UV/IR photography.

[Jim Lloyd]

I Second Ulf comment

 

Regarding the EL-Nikkor80 m f/5.6 lens that I recently purchased - I also bought an adapter for the front filter 34.5 to 52 mm, but it turns out that the front diameter is 39 mm (maybe 40 mm) - its difficult to measure exactly, but its certainly not 34.5. Of course I should have measured before ordering the adapter. Anyone know exactly what size and thread this will be?

[JCDowdy]

Plastic 80mm EL-Nikkor f/5.6N, mount-M39, filter-40.5mm, flange focal distance-73.7mm

See: Sticky: UV-Capable Lenses: Non-Dedicated N

 

 

source: EL-Nikkor sales brochure (1992)

[Andy Perrin]

Jim, save it for when you get a metal EL-Nikkor 80/5.6!

[ulf]

Jim,

 

I apologise if I mislead you to buy the new plastic EL-Nikkor 80/5.6.

This is not going as deep into the UV as the metal types.

 

When I clicked on your two links, I think I saw two versions of the old metal type of EL-Nikkor 80/5.6.

Now one of the links show the new plastic type.

 

The oldest was marked Nippon Kogaku Japan and EL-NIKKOR. The slightly less old metal version only have the EL-NIKKOR marking.

Both of these need the 34.5mm step ring.

 

Keep looking for the metal type of EL-Nikkor 80/5.6.

 

/Ulf

[Cadmium]

More Sparticle UV lens transmission tests (wear goggles) B).

 

I would not waste time with a Tokina 28mm f/2.8mm, tried those, not that anyone here is talking about that, just saying...

 

Then there is this Taisei lens, better than the Tokina I think, but still don't waste time, get a Kuri, best lens I think.

 

You could try a Focotar-2 50mm (no built in focus, needs a helicoid), for much more money ($250 - $500 range) but frankly, I don't see any difference between that and the Kuri 35mm myself (need no helicoid).

Now this comparison was performed with the exact same flash exposure and settings.

 

I like the Kuri, has built in focus and is the best UV lens I have tried.

I don't have a UV-Nikkor, CO60, or the rest of those, but the Krui rocks, and you will probably be hard pressed to show any difference between the Kuri and the more spendy lenses.

Never seen anyone show a difference, still waiting.

Not saying I don't want one to try though. :)

[Jim Lloyd]

Many thanks for all the feedback and valuable information.

 

Regarding the enlarger lens. Yes I realise now that I bought the newer N version (f= 80 mm f/5.6) and I now understand what the aperture window is and I think this does leak. Finally got all the adapters required and taped the filter mount on the front. Here are my initial tests compared to the Optomax 35mm f/3.5 which was the best performing (I think) from my previous tests.

 

Camera full spectrum modified Nikon D3200

UG1 2mm +BG40 2mm filters

ASA 200

4 second exposure

Sunlight outdoors

f/11

 

Beginning to feel like spring here - flowers are Colt's foot and Dandelion (I hope I have got that right!)

 

First the Optomax (requires quite a lot of digital zoom / cropping)

 

 

Now Nikkor

 

 

And cropped portion of this

 

 

UV photography is taking me into new territory as I have always been a landscape photographer before and not looked closed up at things - but beginning to get more curious about this.

 

Overall the EL-Nikkor seems to perform well from the UV point of view and is sharp. I think there are some light leak issues and some lack of contrast. From images and what I have read on this forum it would seem to have similar UV performance to the Optomax - I think?

 

I will keep exploring and experimenting ...

[Andy Perrin]

My first EL-Nikkor was foggy and I ultimately concluded that it was due to hazing in the lens. I got another copy of that lens and it didn't have that problem. I'm not sure if that's similar to your "light leak" issue? My thread on this was back here:

http://www.ultraviol...r-80mm56-tests/

[Andrea B.]

Jim: UV photography is taking me into new territory as I have always been a landscape photographer before and not looked closed up at things - but beginning to get more curious about this.

 

Good! There are some fascinating landscapes-in-miniature to be found.

---

 

Andy -- did you ever take that hazy EL80 apart and try to clean it up?

.

.

[Andy Perrin]

Nope, one of many projects to be gotten to, along with trying to fix the Noflexar. (I got another Noflexar, though.) Do you know any way of making the Noflexar macro extension a little less...stiff? I am pretty sure that is what broke the last one, pulling it in and out so abruptly. I was afraid to play with lubrication because of the fear it might migrate.

[Andrea B.]

Mine all seem to need a solid tug to pull them apart. But I'm thinking you don't want that macro extension to come apart too easily, so a bit of stiffness is OK.

 

You might want to send yours down to KEH.com for a clean & lube. Call them ahead of time and get a cost estimate. I've always found them very reasonable for small now-warranty repairs (if parts are available) and for lens clean/lubes. It is nice every few years to get the lens grease replaced and the lens innards & elements properly cleaned. Lens grease can stiffen or dry with age and also it gets depleted. I'll bet that KEH could put those blades back for you also in the dismantled one.

 

BTW, it's not that we cannot learn to do this stuff ourselves with a few proper tools (like one of those aperture blade manager thingies whatever they might be called) and a little instruction from someone like Dr. Lens to get you started. But if you are like me, there is not always much time available to carefully dismantle, clean and re-grease a lens. Then there are those pesky aperture blades. One little tool flip the wrong way and you're trying to find ap blades in the sofa crevices. Not fun! :P

[Cadmium]

Jim, Those are nice. My favorite is the top one using the Optomax, nice color, contrast, sharpness, and white balance.

I don't have that lens.

 

I have these + more. I think sharpness here is only my fault, not the lenses, just a test for UV transmission depth of lenses.

[Jim Lloyd]

Thanks Steve

 

Do you have the new version of the EL-Nikkor 80mm f/5.6 for comparison ?

[Cadmium]

Hi Jim :-) No, I only have the older version of the El-Nikkor 80mm. It is well known to be one of the best,

[Andrea B.]

Do you have the new version of the EL-Nikkor 80mm f/5.6 for comparison ?

 

Jim, the comparison between the old & new EL-80 is not so much "reach" as it is about transmission. Around 365nm the old EL-80 transmits at about 80% and the new EL-80 transmits at about 50%. So while both will get the job done between 365 - 400 nm, the newer one will require longer exposures. At 400nm the old has 90% transmission, the new about 77%.

Just be sure to block any light leak from the aperture window on the new EL-80. And test your helicoid for light leakage when fully extended. Not every heli is useable at full extension for UV photography.

[Jim Lloyd]

Thanks Andrea

 

So in theory the main difference should be exposure time, between the old and new versions (all else being equal) ?

 

I am not sure if its a light leak, but I noticed a colour variation across the image. In the image below the background slab is a uniform (ish) grey and it looks like that with the Optomax lens. With the Nikkor when I try to white balance there is a backround gradation from magenta to green. Anyone any idea what might cause that? there also seems to be a faint haze across the image (maybe?)

 

 

As a related question. I am attaching this lens to Nikon f mount, and I know that I wont be able to achieve infinity focus without additional lens, but what sort of range should be achievable. I have a 17-31 mm helicoid plus a 10 mm spacer and very roughly I would say I can focus between around 0.5 m to 100 m. Is this what you might expect for M42 to F without an additional lens?

[JCDowdy]

The difference between the flange focal distance of the 80mm EL-Nikkor f/5.6N and the register depth of a Nikon is 27.2mm (73.7mm-46.5mm).

 

As long as the total length of your F to M42 adapter plus helicoid is less than 27.2mm you should be able to focus to infinity.

 

Replace your 10mm spacer with a 5mm and you should be OK.

 

Also try covering the aperture window with black electricians tape to see if that cleans up the image.

[Andrea B.]

With the Nikkor when I try to white balance there is a backround gradation from magenta to green. Anyone any idea what might cause that? there also seems to be a faint haze across the image (maybe?)

 

When you post a photo and ask questions, please be sure to state what camera, lens, filter and illumination were used so that we can best help you !! ;)

 

Color gradations like you have there can be from Light Leakage or from Light Flare or from the Angularity of Dichroic Filtration or from the Shiny Filter Problem or from Stacked Filters. Not knowing what was used for that photo, I'm not sure I will be correct but looks to me to be some lens/filter light flare. Sometimes a left-to-right flare like this might not be noticeable in the Visible rendition of a scene but is quite visible in the UV version because of the white-balanced false colour.

 

Here is the run-down, anyway.

 

Light Leaks commonly happen in the following areas and are usually seen in the photo as a fairly well-defined area of brighter light which always occurs in the same place. (Like a streak across the middle or a bright blotch in an upper corner and so forth.)

• Viewfinder. (Must be closed or covered if not closeable.)
  
• Top LCD. (Tape over or cover it if leaking.)
  
• Back LCD, perhaps? (I've never had a leaking back LCD, but I suppose it is possible.)
  
• Lens aperture window. (Several ways to fix.)
  
• Helicoid. (Leaks often occur at full extension.)
  
• Warped lens mount. (This is bad for many reasons and requires factory repair.)
  

.

Angularity of dichroic filtration: (or whatever this is called !!)

Faint false-color contamination is more likely to happen when a dichroic filter is used on a wide-angle lens. But I've seen on occasion with almost any lens if conditions are right. (Or wrong, as the case may be.) It is typically seen as faint false-color rings at the edges of a UV photograph caused by light which enters at an angle to the plane of the dichroic filter. The contamination can sometimes can be reduced by using a lens hood or by simply changing the angle at which you are photographing the subject. IIRC, rear-mounting a dichroic filter might also help. BTW, I almost never see dichroic rings when shooting close as for my botanical subjects.

It is usually a good idea to also have a UV-pass filter of the absorption type for use on wide angle lenses.

 

 

Light Flare:

A common problem, whether shooting UV or not, caused by light entering the system at an angle to the lens axis or from shooting directly into a light source. You already know the usual remedies: Don't shoot into the sun. Use a lens hood.

 

 

 

The Shiny Filter Problem:

The usual dichroic filter has a very shiny hard coating -- some, it seems, shinier than others. The BaaderU has that shiny Pink side facing out, for example. But its other, greenish side is also quite shiny. These mirrored filter surfaces can cause the entering light t o get bounced around inside the lens and camera chamber. Depending on how the lens and chamber are constructed, you can get some fairly fierce reflection artifacts. I once had a nice image of a lens' inner element fittings (rings) and grooves superimposed on a landscape scene. You can usually re-shoot at a different angle to avoid this kind of reflection artifact.

 

Filter shininess can also cause a big faded, low contrast, "veiled" appearance in the center of the photograph which cannot be cured by changing position of the camera/lens and cannot be repaired Photoshop. (Very minor veiling can often be mitigated by increasing global and/or local contrast.) I have, for example, an expensive hard-coated (sputtered) bandpass filter, the Edmund 340bp10, which is utterly useless because I cannot mitigate its washed-out effect.

 

 

Stacked Filters

Somtimes stacked filters (i.e., two separately mounted filters screwed together, not referring to glued layers) can induce some flare or reflection problems because of the air gap between the filters or because of differences in refraction index between the two filters. I haven't really seen this very often, but it should be listed as a possibility. Same remedies as above - move around and shoot at a different angle, try a lens hood, don't shoot into the light.

 

 

^{Please alert me to any typos or needed corrections. Thanks!}

[Andrea B.]

P.S. Jim, because this is UV false colour I think you would be permitted to paint the background of your photo a nice "rock grey" in Photoshop if you had the patience to do so. Would that really be considered 'Shopping the photograph? :D :D :D

[Jim Lloyd]

Thanks Andrea for your very comprehensive reply.

 

This was a continuation from before, but sorry for not making that clear

 

This is the equipment info:

 

EL-Nikkor 80mm f/5.6 N

 

Camera full spectrum modified Nikon D3200

UG1 2mm +BG40 2mm filters

ASA 200

4 second exposure

Sunlight outdoors

f/11

 

[Jim Lloyd]

PS

 

Looking at your list I conclude that it is a light leak as I didn’t get this problem when using identical set up , but with a different lens.

 

I will do some more testing once spring returns - it has been temporarily cancelled here!

[OlDoinyo]

Light leaks can be a bear...and some of the worst are IR leaks, which can sneak into the tiniest crack in the optical train and then proceed to ruin your image with all manner of unwanted artifacts. It doesn't help that your sensor may be 10+ stops more sensitive to IR than to UV. Many older lenses are prone to IR leaks. Sometimes electrical tape in strategic spots is the best remedy.

 

Dichroic artifacts tend to be centrosymmetric, not uniform gradients across the entire frame.

 

The veiling of the 340bp10 must be very bad indeed if you cannot remove it with Levels sliders.

 

Hot spots can result not only from light bouncing off filters but also off lens element surfaces and off the sensor itself. Film is less prone to hotspotting because the emulsion is less shiny than a digital sensor.

[Cadmium]

Jim, I could ask you for another RAW NEF file of your above last pic to play with the white balance... or I could just ask you to settle on a lens,

but that would defeat the reason for all of this I suppose.

Fact is, if you want a good lens for UV, then you want the older El-Nikkor 80mm (of the newer and older version), and I have no comparison between that and your Optomax.

It is only academic what the difference is between the new and old El-Nikkor 80mm.

Settle on a lens, and go take pics, field time is better.

As I have said, the best lens for UV under $1,000.00 is the Kuri 35mm. My opinion. Find one, and be happy.

[Jim Lloyd]

Thanks Steve - Still looking!

 

I do like the Optomax 35 mm f/3.5 that I have except that it has a fault - the aperture ring moves freely, rather than clicking into the stop positions, Not too bad as I just stick some "blu-tack" on to stop it moving and leave it at f/11 most of the time. Also has a preset ring which is useful and is supposed to move freely, although it's a bit too free and very easily knocked to the wrong position. Anyway I am on the lookout for a copy of this lens in better condition, but it works for me Ok at the moment.

 

Yes - must get in the field - just that winter has made a rather unwelcome comeback here at the moment - "beast-from-the-east III" !