UV rendition of various lenses compared

[nfoto]

I thought about time to set up a little experiment to show how various lenses render a well-known UV subject.

 

For the informal comparison, I choose a flower of Marsh Marigold (Caltha palustris; Ranunculaceae). This species has deep yellow 'petals (actually, sepals), which under UV light show a large basal patch.

 

Here are a few views of the setup taken with a 120 mm Medical-.Nikkor lens on my Nikon D500.

 

 

 

I did the comparison in broad daylight, under a slightly shifting overcast sun. Thus exposure values are not directly comparable. Suffice it to say that the dedicated UV specialists have several stops shorter exposure time than the remainder of the bunch. I will not try to quantify the difference, though, as the natural light conditions were not controllable. One has to do this say in a studio set up with variable flash output to arrive at more specific estimates of the difference involved.

 

The following lenses were tried out, in no particular order, on my Nikon D3200 with internal Baader U2 filter.

• Coastal Optics 60 mm f/4 APO
  
• Nikkor 50 mm f/1.8 AIS ('long nose')
  
• Nikkor 85 mm f/1.4 AIS
  
• UV-Nikkor 105 mm f/4.5
  
• 55 mm f/2.8 Micro-Nikkor AIS
  
• AF 105 mm f/2.8 Micro-Nikkor
  
• Nikon 100 mm f/2.8 SE
  
• Bellows-Nikkor 105 mm f/4
  
• 55 mm f/3.5 Micro-Nikkor P (my earliest sample of the 'Compensating' type)
  

Common to nearly all non-specialised lenses is a focus shift when they operate in UV, ranging from moderate (55 mm f/2.8) to severe (various 100/105 mm lenses except the UV-Nikkor). Thus either a focus recalibrating on the distance scale, or better, using LiveView for focusing is highly recommended.

 

I processed the D3200 NEFs in my standard work flow with Photo Ninja as RAW conversion engine. A w/b for each frame was set on the PTFE discs. I'll return to the question of whether the w/b for a given lens also is valid for another later.

 

These are the UV reference shots, taken with the Coastal Optics and the UV-Nikkor. They both as expected delivered basically identical frames, thus the main differences are the working distance and angle of coverage. The 'shininess' of the sepals relate to angle of incidence for the photograph and the presence of a point light source (sun).

 

Coastal Optics 60 mm f/4 APO:

 

UV-Nikkor 105 mm f/4.5 lens (same camera distance as the previous example):

 

 

The image magnification of the UV-Nikkor capture is around 1:5, which is a little low for showing fine detail such as conical cells.

 

Let the above be the baseline for the next post, which will deal with the non-specialist lenses. As I did not add any extension, some would not focus closer than approx. 1:10 and I used that magnification as a common denominator. The various Micro-Nikkors of course would focus to much higher magnification, if required.

[nfoto]

Here are the various non-specialised lenses with the same Caltha flower in UV, using the Nikon D3200 with built-in Baader U2 filter. Each frame is individually white-balanced against the PTFE discs.

 

I tried to hold exposures limited to less than 2-3 seconds in order to avoid too much blur from wind movement. The day was mostly quite calm, with the occasional gusts. This meant I had on occasion to increase ISO from the baseline ISO 100 to ISO 200, and/or open the aperture from f/11 to f/8. Now and then the sun broke out of the slight cloud cover to make its impression by more distinct shadows. I shot with or without Liveview control of the focus, but only the focused image is shown here. Depending on what capture came out decently sharp, I show either the overview image or the one at the near limit. Bear over me for this as natural light and wind are tricky adversaries for comparisons.

 

AF Micro-Nikkor 105 mm f/2.8 (large focus shift):

 

Nikkor 85 mm f/1.4 AIS (small focus shift for close-up, virtually none for distant scenes with the lens stopped down):

 

Micro-Nikkor 55 mm f/2.8 AIS (only a small focus shift):

 

Micro-Nikkor 105 mm f/4 AI (moderate focus shift)

 

Nikkor 50 mm f/1.8 AIS ('Long nose', early version with sn. 31xxxx. Moderate focus shift):

 

Certainly these results give a lot of food for thoughts.

[nfoto]

The final example is the question of white-balancing our 'UV colours'. Yes, of course they are false, but we know well they can be made reproducible to a great extent.

 

When I shot UV subject, I normally use one or at most two different UV specialist lenses Costal 60 APO and the UV-Nikkor). Setting a session w/b by profiling one of the frames and paste this to the others in the batch works very well. However, this might not always be the case.

 

Here I first obtained a w/b from a frame with the 50 mm f/1.8 AIS. The actual frame of the 50/1.8 is here,

 

 

Next is pasting this w/b in Photo Ninja to that of the capture with the Coastal Optics 60 mm f/4 lens ;

 

 

We can go in the opposite direction using the Coastal Optics frame as a w/b reference for the 50/1.8 Nikkor. The original CO 60 frame is here,

 

 

Then, here is what we get by using that w/b for the 50/1.8 Nikkor capture above,

 

 

The immediate lesson to be learned is that only lenses with a compatible spectral behaviour can be treated as equal by swapping w/b settings. Otherwise we must profile each frame individually.

 

The false colours of the properly profiled photographs are broadly similar, but the UV specialist lenses do exhibit much more saturated and vibrant colours. These lenses also show UV-absorbing flower patches as near jet black.

[Andrea B.]

An excellent contribution, Bjørn. Thank you!

 

It was important, useful and very interesting to include all the "ordinary" lenses in your survey. :)

(ordinary = no fluoride or quartz elements, not made specifically for UV use)

 

I've wondered for quite some time why we work so hard to find UV-capable lenses for our UV photography when it seems clear that ordinary lenses work well enough in the 370-400nm range (approximate). Any any deficits in saturation and vibrancy from these lenses can be tweaked in the converter/editor to some extent.

 

Of course, aside from their wide UV transmission, I get that the reason for using lenses such as the CO 60/4.0 and the UV-Nikkor 105/4.5 for UV photography is that they are superb as lenses: sharp, high resolution, very low colour aberrations, good contrast, well-made.

 

A note about your WB colour swapping: Timber showed that some time back and postulated that it can tell us something about the UV transmission of the lens. Oldoinyo (Clark) also has shown a version of this and drawn the same conclusions. Your WB swap of the CO 60 onto the 50/1.8 shows a shift towards the blue which seems to indicate that the 50 does not reach deeply into the 300-400 nm range.

[nfoto]

I concur with the latter analysis, Andrea. One can in fact infer this by the false colour rendition directly (assuming they are properly adjusted in the RAW editor), as the not-so-deep-into-UV phalanx always exhibit pale colours and whatever part the deeper ranging lenses show as black in UV, they present in lighter shades often greenish tinted.

 

Based on my findings, I would go so far as to state that getting a nice, clean sample of the Micro-Nikkor 55 mm f/2.8 is the most cost-efficient way of entering the world of UV photography, if your main interests are flowers and suchlike objects. In this informal test comparison, it delivers 85-90% of the detail information of the Coastal Optics 60 mm APO or UV-Nikkor 105 at a tiny fraction of the cost. Even cheaper alternative apparently is the old 50/1.8 AIS, but then one has to add extension to move in close. Frankly I was amazed of the quality these two delivered in the current test.

 

All the above hinges on the assumption that one wish to record patterns in UV that manifest themselves say 370-390 nm, ie. in the upper end of the passband of the Baader U filter. I have no high expectations of them being able to cope equally well further down in the UV range recordable by our modified cameras. However, they should service well for recording of UV floral signatures. A further plus point is that these lenses exist in abundance on the second-hand market, prices are very acceptable right now, and nobody has inflated their "UV Value" so far.

[Andrea B.]

Thank you for those further insights. This will give me something cool to link to in the Lens Sticky.

 

Would you please add anything specific about the two models of the following lenses which might be relevant for folks wanting to buy one in case there were different models made at different times? I can go to Roland Vink's site and check for various models, but which ones specifically did you use?

• Micro-Nikkor 55 mm f/2.8
  
• Nikon 50mm f/1.8 AIS
  

[nfoto]

Micro-Nikkor 55 mm f/2.8 AIS. Must be at least 100.000 of them made.

 

http://photosynthesis.co.nz/nikon/ais5528n.jpg

 

Watch out for any obvious signs of lubrication seeping onto the diaphragm blades (oily residue). The higher serial numbers (newer) tend to be better in this respect.

 

The 50/1.8 exists in a lot of variations internally and externally. The one I used is known as a 'long nose', and its serial number starts with 31xxxx. It focuses to 0.45m. According to Roland Vink's site http://photosynthesis.co.nz/nikon/serialno.html, more than 150.000 were made.

 

http://www.destoutz.ch/slides/lens_50mm_f1.8_3209712.jpg

[OlDoinyo]

For those whose kit is not Nikon, I would put in a word for the Steinheil Cassar-S in M42 or similar universal form as a fine starter lens. Dr Schmitt made me aware of that one, and like the above, it costs perhaps 5% of what a "real" UV optic does.

[nfoto]

Anyone feel free to repeat my little experiment with other lenses. I simply availed myself of the lenses at my disposal that also had a CPU inside to uniquely identify them in the later processing work flow.

 

However, I also wanted lenses that could work with full automation on my cameras. Not everyone is set on that prerequisite.

[kogakunippon]

Thank you very much for this test. It showed me what I thought long time already, namely that many "normal" lens can also be used in UV with just small shortcomings.

[nfoto]

Keep expectations of 'deep UV penetration' low and many lenses can help you get the UV image you need.

 

Still, one can do oneself a favour by avoiding the latest generations of multi-coated, multi-element optical designs and instead hark back to the '60s, '70s or at most early '80s for candidate lenses.

[OlDoinyo]

One should also consider the most likely subject matter when debating what the best starter lens is. Do you expect to shoot flower macros, portraits, or landscapes? For the first, a short telephoto length with close focusing is important. Landscape photographers might prefer a normal (~40 degrees' field of view) or wide-angle lens. Portraits do well with short telephoto optics as well, but close focusing is less important. If you don't know, perhaps a normal lens with close focusing is a good compromise. Do not, however, expect to be able to use teleconverters.

[nfoto]

Unless you "build" your own TC.

 

I have modified 2X TCs from the old Petri system to work with my Coastal Optics 60/4 APO and the UV-Nikkor 105/4.5. There is of course a loss of image quality and UV sensitivity, but as the master lenses are of very high quality, the final outcome still is very satisfactory. Infinity focus is retained on both lenses.

[kogakunippon]

I really love this Forum and all the conclusions. Just with reading your Posts I have learned so much in the past weeks, and I really want to say thanks for that.

 

But there is one question for me:

 

Why virtually all UV photographers deal here exclusively with flowers instead of trying landscapes?

 

I am well aware that the sky during the day is always ugly white and it does not look pretty in purple monochrome photos, but nevertheless it was still almost never tried, right? And for landscape photography are short telephoto lenses not really useful because wide angle optics would be much more practical. But Tests of UV grade wide angle lenses are not yet done, or am I wrong?

[nfoto]

Good to hear you find the forum useful ...

 

As to the emphasis of flower photography, I think this partly has historic reasons (I'm a botanist by education), partly due to the fact that often infinity focus in UV can be difficult to reach for system used. Besides, the distant areas of the landscape tend to be very hazy and low in contrast in UV. Often it feels like one shots in fog.

 

We have evaluations of wide angle lenses for UV work, and most experiences are these are not very UV sensitive. Plus, filtration can be a deal-breaker unless rear-mounted filters are feasible. The three wide lenses used by me are the Tamron 21 mm f/4.5, Nikkor 18 mm f/4 AI, and the Fisheye 16 mm f/3.5 AI. All can reach infinity in UV on my modified Nikon D3200 with built-in Baader U filter.

 

Personally I think the requirement of wide angle lenses for landscapes really is a myth and that better landscape photography can be done with longer lenses. I prefer 85 to 200 mm or longer for this kind of work.

 

However, as demonstrated by the Caltha photo below, a wide-angle lens can come in handy to document the biotope. This was taken with the Tamron 21.

 

[Alex H]

Wolfgang, you are missing a lot of information by not searching the forum.

 

Why virtually all UV photographers deal here exclusively with flowers instead of trying landscapes?

 

http://www.ultraviol...st-storangsudd/

 

http://www.ultraviol...h-of-stockholm/

 

There are many many others, especially posts by Clark.

 

And for landscape photography are short telephoto lenses not really useful because wide angle optics would be much more practical. But Tests of UV grade wide angle lenses are not yet done, or am I wrong?

 

50mm lens: http://www.ultraviol...rthern-florida/

 

35mm (#1-#3) and 100mm (#4) lenses http://www.ultraviol...s-and-pastures/

 

But Tests of UV grade wide angle lenses are not yet done, or am I wrong?

 

One of the many tests published: http://www.ultraviol...ide-angle-lens/

[kogakunippon]

Thank you very much Alex!

 

I have seen most of this photos an the wideangle test, but the 20mm Oympus Pen lens can't be used on my Nikon Body and 35mm on DX is everything but wideangle ;-)

 

Each lens with a filter Mount over 52mm is not easy to handle because of the Baader U size.

[nfoto]

Rear-mounting filters is an option, but not always easy to implement. Sometimes a modification of the rear end of the lens is required.

 

Using a mirrorless camera with shorter register may allow placement of the filter inside a lens adapter. The drawback is the formats may be smaller than DX/FX and thus field coverage is narrowed. The Sony range is an exception by offering FX format.

[Alex H]

Than you have to make a hard choice between the camera you want to use and the pictures you want to take. Or buy 77mm diameter UV filter stack... Or a panoramic tripod head...

 

P.S. I personally chose my camera equipment based on the type of pictures I want to take.

[kogakunippon]

Rear-mounting filters is an option, but not always easy to implement. Sometimes a modification of the rear end of the lens is required. Using a mirrorless camera with shorter register may allow placement of the filter inside a lens adapter. The drawback is the formats may be smaller than DX/FX and thus field coverage is narrowed. The Sony range is an exception by offering FX format.

 

Thanks for all your Input Bjorn. How did you manage to get the Baader Filter into your Nikon D3200 if I may ask that?

[kogakunippon]

I personally chose my camera equipment based on the type of pictures I want to take

 

Thats a smart advise :-)

 

I will take UV landscapes at night in Japan (there is no utraviolet light at night, I know).

[nfoto]

... How did you manage to get the Baader Filter into your Nikon D3200 if I may ask that?

 

Courtesy of my friend Vivek Iyer. I understand cutting these filters is a very risky business and one has to accept that some units are broken during the process. If memory serves the breakage was 50% for this project.

 

Vivek initially cut the filter for a D40X, which is a very nice camera and its UV sensitivity is really excellent. The D40x also has proven itself to be surprisingly robust under field conditions. However, the camera lacks GPS (a feature most important to my line of work) and when an offer of a pristine D3200 at a low price crossed my path, I could not resist. The filter was, admittedly with 'some' practical difficulties, transferred from the D40XS to the D3200 and the D40x converted to IR instead. The D40x still is my IR backup camera and lives in a crate in my car in companionship of a GPS logger.

[OlDoinyo]

 

Why virtually all UV photographers deal here exclusively with flowers instead of trying landscapes?

 

 

Check out some of my images.

 

As to landscape photography, a wide variety of focal lengths is more paramount than any single focal length. I take landscape photos all the way from 14mm to 500mm. I would say that the most-used lens for me is 35mm, but that is not the majority of exposures.

 

A white sky is not always ugly, and not all UV skies are white.

[Jonny]

Based on Bjorn's test I tried out my Nikon 50mm AF (original version) and I was surprised by its performance. Using a U340 and S8612 on my D3100 it came very close to the 35mm 3.5 presets I own and the Weltblick 55mm. It beat the Nikon 35mm 2.5 E by a long way. I would say it beats the Novoflex but I sold mine earlier this week

 

 

Ironic that I spend so much time chasing exotic lenses, only for the ubiquitous 50mm to come up trumps...

[Alex H]

Jonny, in what way it is better? Speed, sharpness, transmission? We all are looking for different properties in our lenses. I would be glad if you can clarify your statement.