I’ve been scanning a load of my parents’ and grandparents’ old negatives. Amongst all the fuzzy shots of relatives on holiday was one film’s worth of long-term shots taken in my parents’ garden. They were taken by me of a family occasion. I had obviously given both the prints and the negs to my parents so they could make reprints. I’d forgotten all about the pictures and the occasion. But aside from that, I’d forgotten how good a long lens is for pictures of people.
These days I tend to use standard to wide angle lenses. I get environment and context in the shot. But the simple joy of seeing a single figure separated from background, not particularly aware of your presence – it’s great.
It was a sunny Summer day and I was using 200ISO colour negative. I only had two long lenses at the time and it was obvious from the shots that I didn’t use the zoom. So these were shot on a 135mm lens. It was bright sunlight and I know I was shooting with flash, so the fastest shutter speed I could have used is 1/125 which means this lens must have been stopped-down and not wide open. It still blurred the backgound nicely though.
I think this focal length has gone out of fashion: it’s thought to be too long for portraits. One of the photo podcasts described it as a focal length that was invented to let German hill-walkers pick out a detail on the other side of the valley. I guess it would be too long for indoor portraits, but it worked perfectly in my parents’ garden. I’ve even got full-length portraits.
So I’m back in love with the 135. The one I was using at the time was a Pentax – the SMC Takumar f2.5. In the years since the aperture blades have become oily and slow, so I need to send if away for some TLC. But a Vivitar f2.8 came up on eBay at under ten squids and now it is mine.
Back in the old days we used to know that with a 50mm lens on 35mm (or full frame) held portrait, a person would nicely fill the frame at about ten feet. I just did the sums again and the field of view for a 50mm lens on a vertical 35mm frame is two meters at nine feet (ooh, nice mixed metrics – it’s 2m at 2.8m distance).
Slap a 135mm lens on and the distance increases to 24′ (7.4m). So yes, you’re unlikely to be shooting full length portraits indoors. I do like the effect though and it will come in handy with our current distancing and separation.
Down sides? I had obviously not used the Pentax lens much in recent years. Perhaps it really was a bit too long for people and not long enough for sport. I do remember that it was never out of my camera bag at the time. Perhaps then it was just me changing the sort of thing I shot? Maybe I got old and slimmed-down the camera bag?
So it looks like I’ve rediscovered the modest tele lens. Let’s see what I do with it during my government-allowed exercise period.
Remember the film title Things to do in Denver when you’re dead? Well this is things to do in the house when you are trying to not be. In the house I mean, although not being dead is important too.
Despite all the therapy and support, in times of idleness one’s fancy can turn to things of bokeh. Or the unimportant bit, as we used to call it. That’s when you realise you have several lenses of the same focal length but different construction. And you wonder why, and what the difference is between them. And if the really clever or expensive lens is actually better than the cheap one. And what better means. And if this means you need to buy more lenses. Or find better backgrounds.
So you find the adapter that mounts your cheapo nasty analogue lenses on your digital camera. This takes two hours and uncovers more interesting old lenses. But you only have one version of each of them. So when it gets dark and eBay closes for the night you come back to the plan. One focal length, one aperture, one scene: the ultimate shoot-off. But is it fair to compare a lens that can do f1.2 with a lens that has a maximum aperture of f3.5? Do you compare them all at the same aperture or at their widest? More time passes.
After a few more beers you decide that the reason you started this (and it is totally your fault) is to see what the backgrounds looked like. Kind of an aide memoire of which lens to use to get which effect. So it’s fully open aperture on all lenses to get the best of their aberrations. But to use a scene where the point of focus is close, so that we get lots of the fuzzy. And we reassure ourselves that we haven’t gone all Photography With Classic Lenses and that we still have a sliver of pride and self respect. And then we laugh and drink more beer.
So – big question: what sort of fuzzy does it for you?
Me? I’m a smooth guy. I like the out of focus areas to just look less sharp. I want my background to be background. Smooth tones. No magic circles or swirly. Nothing that looks like the subject is stood in a whirlwind or bubblebath. The only reason to use the weirder lenses might be that the pattern in the background somehow adds to the shot. Otherwise it’s the background. But that justifies the other lenses, right?
Now, some of the theory to this is that the rendering of the background is affected by how well-corrected the lens is for spherical aberations. And a simple magnifying-glass lens gets better corrected for other aberations by adding more elements to the design along with different types of glass. It’s fairly easy to make a reasonable lens at small aperture sizes, but the wider you want the lens to be the more clever the design has to be, which often involves yet more bits of glass. So the argument is that a simple lens ought to have more textured out of focus areas than a more complex and better-corrected lens.
So where does that leave me on a Sunday afternoon? I have, in the same focal length, lenses with from 3 to 7 elements. I have lenses that span the all famous design formulae. To be honest, I have a sufficiency of lenses. And I have time.
So, the simplest lens is no lens. But I have no pinhole cameras at the moment so this is out. Same with a simple meniscus (but been there, done that on medium format) or a doublet. Got a triplet though.
So I’ve got:
Triplet – a Meyer-Optik Goerlitz Domiplan 50mm F2.8.
Four elements in three groups (Tessar) – an Industar 50-2 50mm f3.5.
6 elements in 4 groups and probably a Planar design – Rikenon 50mm f1.7.
6 elements in 4 groups, but a Biotar design – Helios 44 58mm F2.
7 elements in 6 groups, probably a version of the Planar – an Auto Yashinon 55mm F1.2.
This is what I had to hand – I am not spending time on eBay looking for a five element lens.
Now, everyone buys the Domiplan lens because it does bubble bokeh: out of focus highlights turn into circles. With only three lens elements, it doesn’t really correct for much at all.
At the other extreme, the Yashinon has seven elements, not so much to make the lens sharper but to manage the aberations in a design that is more than two stops wider than the Domiplan. Somewhere in the middle might be the sweet spot of fast enough and smooth enough – the Goldilocks lens.
My first idea was to shoot them with a nearby lamp as my subject and a window behind to give me some highlights. That didn’t really work, as they all looked quite similar. The only one that stood out was the Yashinon. This was because the design that was pushed to work with a front element almost two inches in diameter caused some crescent-shaped highlights away from the centreline of the lens. This is the downside of pushing a lens design this far.
So instead of dithering indoors, I persuaded Wilson‘s cousin Gilbert to stand in as my model in the garden. He’s a rugged fellow with plenty of skin texture, so ideal.
So, what do I think?
Well, one thing was that some of the lenses had noticeable field curvature. In each case I focused on the B in the centre of the lens than reframed the shot. In some, like the Domiplan, the sharpest point has moved nearer the camera. Something to be aware of – I can’t just reframe some of these lenses if I use them wide-open.
The Domiplan is a cheap lens that does the bubble trick on background highlights. It’s OK for that but it can make the background look quite busy.
The Industar 50-2 is great – I really like this lens. It’s tiny and it renders backgrounds smoothly. A bit of a pain to use though, as the aperture is manual.
The Ricoh/ Rikenon is the standard lens that came on my first SLR camera. It does a good job and doesn’t intrude. It works on my film kit and on the digital and gets the highest praise: it just works.
The Helios is a real cult lens because it can make backgrounds look swirly. It’s slow to use, as mine is one of the older ones with a preset aperture. Given the choice I would usually take the Industar, because it is so much smaller and lighter than the Helios.
The Yashinon is bonkers. It does crescent-shaped highlights, it does completely fogged backgrounds, it can see in the dark. On digital it also gives coloured fringes and a bit of a glow to things – see the shots above. Unless you want to shoot at F1.2 all the time it needs to be used on a proper M42 mount, so I use it for film work.
My conclusion? The Domiplan and the Helios are special effects lenses. The Industar is a superb pancake lens with good rendering. The Ricoh is a rock-solid standard. The Yashinon is there for when you really do need to separate the background or to take pictures in the dark. And your mileage may vary.
It happens sometimes. Not every time, but often enough that the pleasure compensates the pain.
I opened the developing tank and unspooled the film to hang it up to dry. It was shot under varying conditions with a simple meterless camera. All the frames look consistently exposed. A good start.
Then I scanned them, and a little song started in my heart. One frame was an experiment based on something I heard on the Studio C41 podcast. They were talking about large format photography and exposure, and it relates exactly to what I have been thinking about. The point of the discussion was to meter and expose for the shadows and let the film latitude and a compensating developer take care of the highlights. Basically – overexpose.
I had exposed for the shadow cast by a sunlit willow tree and the scan shows loads of detail in the shadows and luminous highlights. You can colour me happy. I’m not a great fan of landscapes, but I had been shooting some while we were in Anglesey. Those pictures made me happy too – black wiggly trees on white sand. This is what it’s all about. As the man said “I enjoy photography because it makes me sad and I hate the outcome, said no one ever”.
At the end of the roll were a few frames I had shot with a new lens. New to me: it was made in the seventies. A couple of shots of stuff at infinity and a few taken as close as I could get and showing plenty of background. Very interesting, and another wee thrill for my jaded senses. The out of focus areas look rather interesting, and very different to the lens I used for the willow tree and landscapes. So interesting, that I want to see what it will do to colours. So onto the digital camera it goes, so that I can get immediate feedback.
Very interesting again. Very smooth backgrounds when close, tending towards a bit of swirly when further away. I need to try this on some portraits as the vignetting looks ideal. Plus it made me play with the digital SLR, which has been a bit neglected of late. I remembered that it has a feature of being able to take multiple exposures and merge them into a single shot, adjusting the total exposure. So I got the manual out and had a go. So that’s a new trick in the bag for when the right time comes along. The camera is an older generation digital, so suffers from noise when you use high ISO. So what I’m thinking is to shoot night skies by combining a series of longer exposures at lower ISO. This might also average-out the noise.
Happiness: enjoying what you have done and being excited to do more. Yay!
So, knowing that I used to be Beaker in a former life, this is how I interpret the title of this post. Enjoy.
Gotta love a standard lens. Not too hard to get good performance out of, and there used to be one attached to every changeable-lens camera that was sold. There’s a lot of them about and they can be reasonably priced.
I have been using a wide-aperture standard lens that I got from a charity shop. It was a bit of a punt, as the rear element looked like it was chipped at the edge. But if you imagine that the lens throws a cone of light at the film plane to cover a rectangular frame, the damage was lined-up with the long edge of the film. I hoped that this would put any problems well outside the actual area captured by the film. I also painted the chipped area with black paint. It was worth a try, and how else am I going to get an f1.2 lens for the price of a coffee?
It renders nicely, and the out of focus areas are busy but interesting. (Eek! I’m turning into a bokeh monster)
It can get a bit too busy if there are highlights in the background though.
The chip in the lens is a bit odd though. There is no damage to the lens from being dropped and the design of the lens almost means there has to be a cutaway in the rear element to clear the aperture-operating pin. If anyone else has one of these (Tomioka Auto Yashinon 55mm 1:1.2) do let me know what a good one looks like. And yes, I know this lens uses radioactive glass. It’s an alpha emitter, so stopped by a lens cap.
I’ve also got an Industar 50-2. This is a weird little Soviet pancake lens that came with a Praktica as a rear cap. The maximum aperture is f3.5, but it renders backrounds really smoothly.
This cost the equivalent of a couple of fancy coffees. Probably less, because I don’t drink CostaBucks so I don’t really know what they cost. It vignettes a bit when wide open, but that adds to the results when I use it as a portrait lens on a crop-sensor digital camera (making it equivalent to a 75mm).
I’ve also got a Helios-44 which does the swirly background thing if you get close.
I’d also like to point out that my versions of these lenses seem to break the golden rules of lens-buying. What we are told is that scratches on the front eleement are OK, but don’t buy anything that has damage to the rear element. Avoid lenses with fungus – except the Industar 50-2 had spider’s webs instead. And if you buy a Helios-44, get one where you can turn the focus ring. Mine is so stiff it unscrews the lens rather than focusing.
Don’t care though – they cost peanuts and I enjoy using them because of the results.
So I got curious enough to go and find what my ‘chipped’ lens looks like, and it appears that the cropped rear element is a real thing and was made that way. I can only think it must have put other people (than this chancer) off, which is why it was cheap.
I have just found what these f1.2 lenses sell for. Eek! This is very far from a thrifty fifty. So, do I sell it to fund some other work, or keep it to continue playing with?
Lens hoods – a good thing all round. There are those clever petal-shaped ones, square or rectangular ones to match the film format, the odd but sexy Leica ones with the cut-aways plus various rubber offerings. But what if you need one for a particular lens, perhaps only for a short time? How about making one?
We’re not talking 3d printing here. With a bit of calculation and the kind of drawing set you had at school, you can make a custom lens hood from black paper.
What you are going to make is a frustum, a cone with the top cut off. The narrow end of the frustum will fit over the front of your lens. The angle of the sides will match the angle of view of your lens. The depth of the hood will be what you want to make it, limited only by the size of your sheet of paper. There are some calculations involved, but I did this once in a spreadsheet so I only need to enter the key measurements to make a new hood.
The first key measurement is the diameter of the front of your lens. The lens hood will need to be a sliding fit over the lens. This measurement is not the filter thread size – measure the actual diameter of the lens.
Next is how deep you want the hood to be. This is handy if you are making a hood for a special situation, like using a long lens in strong side or frontal light.
Lastly, the difficult measurement: the lens’ angle of view. This can be difficult because it’s not just a function of the lens focal length: it’s the relationship between the focal length and the size of the film or sensor. This is why a 50mm lens is considered standard on 35mm film, but a 6×6 negative on 120 film uses a 75mm or 80mm lens.
What could be a right chore is made simple by looking-up your lens and film/sensor combination in previously published data. The BJP had a great article plus graphs in the 116th edition in 1976, but I bet you didn’t keep yours… There is also a useful calculator here.
I’ve got a 55mm lens for a 35mm camera. Looking-up the angle of view from the calculator I’ve linked above, the diagonal angle for a 35mm frame is 43 degrees. I use the diagonal angle because anything less than this is likely to vignette the corners. So this means my lens hood should be a cone with an angle of 43 degrees. I fancy making the lens hood 50mm deep – for no other reason than it feels like a useful compromise between no use and too big.
The last key measurement is the diameter of the lens; in this case 57mm.
So I want to do the trigonometry to calculate a frustum with a 57mm wide hole at the top, the sides sloping at an included angle of 43 degrees and with a vertical height of 50mm. The first time I did this I did all the calculations myself. Then I discovered a dedicated website with the sole intention of providing the calculations needed to effectively open-up a frustum and lay it out as a shape that can be drawn on paper. The formulae look difficult, but it’s simple to put them in a spreadsheet. If you provide cells to put the specific values into – lens diameter, angle of view, depth of hood – the same spreadsheet will give the drawing measurements for any hood that takes your fancy.
I made the calculations for my hood and got three key measurements: two radii needed to draw the pie-slice on the paper and an angle of arc for which I need to draw the curves. In the case of my special lens hood, I need to draw two arcs with radii 78 and 132mm and to draw the arcs with a sweep of 132 degrees.
Here’s a picture.
I used plain black art card. For the pictures I marked it out using a white pen, but for normal use I would use a pencil. I marked a tab at the end of the arc to give myself an overlap that I could hold down with tape. If I was going to use this hood a lot, I would use the tab and a slot to let me disassemble the hood when I wasn’t using it (or I would hold it together with masking tape, which peels off). I also left some extra material on the inside of the smaller radius. This is cut into a number of tabs that will go over the lens and hold the hood in position, particularly if you put a bit of tape on them.
It’s easy to find a protractor, but a large set of compasses is more difficult. I use a bit of card with holes for the tip of the pencil and a pin to pivot on.
Cut out and fitted it works just fine.
This is an excellent way to make a hood for short-term use or for a lens that you would not otherwise be able to fit. Unstick the masking tape and the hood can be stored flat.
There you go – something useful for a change in place of the usual grumbling.
If anyone wants to use my spreadsheet rather than do your own calculations, drop me a comment and I will post it somewhere accessible.
Classic seems to mean ‘not made any more’. I used to be interested in classic motorcycles, but classic came to mean extinct rather than good and some complete dirtburgers were given a rebore and a coat of paint and became “classic”. Never mind that the refurb would have cost more than the bike was ever worth or that people who owned one at the time were only too happy to trade it for a Honda. And the result of all the effort is that the proud owner gets to take it to shows on a trailer and have people tell him that the shade of paint is wrong for that year.
I too rode a classic motorcycle, but it had raised compression, a twin-plug head and a chain oiler, and I rode it to work. Oh dear, I’m getting into reverse willy-waving again. Let’s get back to lenses.
So – a classic lens is one that you can no longer buy new. I did ask and was firmly told that a classic lens is also a fixed focal length: zoom lenses are not classic. From what I can see, the most prized feature of a classic lens is the way it renders out of focus areas, particularly highlights. Remember the mirror lenses that were, for a while, the easiest way for mortals to afford a long lens? There were a load of 500mm f8 catadioptrics to choose from, but their distinguishing feature was the way they rendered out of focus highlights as circles. Pretty much a one-trick pony: once you had seen a picture full of bubbles you probably sold the lens and went back to refraction as your favoured method for bending light. And now people pay big wonga for Meyer Goerlitz lenses that have sufficient aberrations to recreate the effect. Want to do it for cheap? Try a longish lens with a clear filter and a disk of black paper or tape in the middle of the filter. If there wasn’t a Cokin filter that did this I’m sure I could sell you a bubble bokehlicious®️fuzzy duck filter.
A few minutes work with a marker pen and the first Fuzzy Duck filter leaves the production line
Ooh, bokeh balls, yum! The odd texture in them is due to the swirls of the marker pen
So ok, rings is a thing but not the only trick in town. The other things that classic lenses are supposed to be good for is micro-contrast, meaning low contrast as far as I can understand it, and not smoothing-out fine detail (which may be the same thing). But perhaps this only applies to CLASSIC lenses and not just any old bit of second-hand glass. From what I understand, older lenses suffered more with flare and reflections. This could mean that the overall contrast between highlights and shadows was reduced, so kept within the dynamic range of the film. If the lens was a good one and could resolve fine detail, this could be what people call microcontrast. As coatings got better I assume that the overall contrast rendered by the lens increased. It may well be that this exceeded the ability of film to capture it, and the abilities of earlier-generation digital sensors. Digital sensors now beat film on both dynamic range and sensitivity, so I would expect that a modern digital camera with a modern digital-designed lens will render both fine detail and a wide overall contrast. Stick this clever lens on a film camera and you might find it too contrasty. Stick an older film lens on a digital camera and you might find it reduces the overall contrast of the scene, so it needs less post-processing.
There are also some issues with putting older film lenses on digital sensors, in that a digital sensor prefers the light to arrive straight-on, where film doesn’t mind if the rays are oblique. This matters at the edge of the frame, and more in colour than black and white. So some film lenses on some digital cameras produce fuzzy edges or colour fringing.
The main idea seems to be though that older lenses contain magic. They don’t resolve every skin pore, the backgrounds are nicely smooth and not distracting, and the fall-off from sharp to out of focus looks nice. Sensors smaller than the original film size turn old lenses into longer focal lengths (narrower angle of view), so a fairly cheap 50mm film lens can become a very cheap wide-aperture portrait lens. This will throw the background out of focus and isolate the subject better than the zoom lens that came with the camera, and way cheaper than a sharp digital lens of the same size.
But watch what happens with mobile phones and how it will migrate to mainstream cameras. Before long you won’t need to buy a Planar or a Sonnar and deal with fungus or scratches; you will use the kit lens and dial-in your lens effect. The autofocus knows which parts of the image are sharp, so the in-camera computer can add your favourite aberrations back to the fuzzy bits. Pentax released a software developer’s toolkit for their K1 full-frame camera, so this might be where you see it first.
But this idea that old lenses were better than new lenses? Prove it. Technically better, in terms of resolving power, control of flare, sharpness across the image? I doubt it. A more pleasing rendering of the image due to design or manufacturing shortcomings? In the eye of the beholder, but apparently true if you have seen how the prices of some old lenses have risen. Come the revolution though, and I’m hoping the prices drop again as in-camera effects mean that everyone can have a Canon ‘dream‘ lens.
Lenses are marvels of optical calculation and manufacturing craft. So why am I futzing around with old projector lenses and door viewers?
Part of is the joy of orneryness (easy for you to say): the pleasure in solving a problem by going against the grain and taking the less obvious path. Yes, I could spend the kids’ inheritance on eBay and buy a Meyer-Goerlitz lens with magical bubble bokeh. Or I could wrap an old slide projector lens in camping-mat foam and jam it up the middle of a set of extension tubes. There are some fantastic and rare macro lenses out there, but you could also pop an enlarger lens (which is usually well corrected for macro work) on some form of extension tube or bellows.
Something I have been looking at is the Petzval lens. I didn’t know they existed until Lomography started selling them. Nice results, even if you wouldn’t want to use it all the time. A lot of money to put out for something that would spend most of its time in the bag, though. Plus they don’t make them in either of the lens mounts I use. You can get old brass lenses that were made with the Petzval design on eBay, but they too have shot up in price. But the Petzval formula is pretty simple and some projector lenses use it. So I’ve been looking at old projector lenses but also thinking about building my own. There are places that sell lens elements in various types and strengths, so I’ve been tinkering with the maths to find a combination that works. By works, I mean can be far enough away from the film or image plane to allow for the depth of the camera body plus some means of focusing. This sets limits on the focal length of the lens, which in turns sets limits on how wide an aperture I could get.
My camera has a lens flange to focal plane distance of a gnat’s less than 46mm. So, without clever lens designs, the widest focal length I could use would be 46mm. At the long end I’m limited by the diameter of the lens elements I could find. It’s all very well building a 500mm lens, but not if it only works at f22. I might lose that swirly background I was working so hard to obtain. Besides, a long lens would turn into a ridiculous bazooka pipe. So I’m looking in the 80 to 150mm range. Focusing is not really a problem, as I have some magic focusing bellows left over from an earlier infatuation. On the other hand, life is short (and ars longa, even with support pants) so I will probably stick with bodging existing lenses.
Some years ago I was reading an article on Elliot Erwitt and his candid street photography. He was said to use an unusual lens combo: a longish manual lens mounted on a set of macro bellows. The lens was long enough to give a proper infinity focus and the bellows had a rack and pinion to focus. The bellows also meant that he could go from long shot to close-up without changing anything. So like photographers immemorial, I bought the kit to improve my pictures. This was when you could buy all sorts of accessories from Practika and Zenith at almost pocket-money prices.
Actually, it worked. With a 4″ enlarging lens on the front it really did cover a wide range at the expense of manual everything. So the bellows would be my focusing rack for further experiments. It didn’t work for slide projector lenses though. These were too wide to fit into the front of the bellows and the bellows wouldn’t shrink down enough to give an infinity focus. No problem, as bodging baffles brains. Along came a set of very cheap manual extension tubes from China. Then a layer of camping mat foam was wrapped around the lens using gaffer tape, until the lens was a snug fit inside the tubes. Then I had a lovely soft focus portrait lens that worked really well, as long as I didn’t point the camera downwards. The nice thing though is that it works for a whole range of projector lenses. If I need a longer flange distance I just add a couple more bits of extension tube.
For anyone who is interested, the 150mm appears to have smooth bokeh while the 85mm looks like I could get some bubbly bokeh out of it.
Wide angles are a problem though. Proper wide angle lenses overcome the problem with the camera flange distance with clever optics. My 15mm lens can’t be 15mm away from the film or sensor due to the depth of the camera body and the need for a swinging mirror. The clever lens fairies in Japan made it work at a flange distance of around 46mm. But if I want to bodge something wide out of inappropriate parts that flange distance is the wasp at my picnic. And then I read an article on t’interweb… (which I have been searching for ever since). The idea is to use an extremely wide angle CCTV lens. Mount this on tome form of extension tube so that it would focus on a sensor, but leave the sensor as empty space. (OK, just mount the lens on a tube). Then mount this whole thing on the end of a reversed lens attached to a camera. The idea is that the virtual image focused by the CCTV lens is seen by the reversed (strong macro) lens and focused in turn onto a real sensor of film. And if I did the maths right, the macro lens would enlarge the virtual image from the CCTV lens to cover the camera sensor. Plus, a fisheye lens for a CCTV camera is not big bucks. Plus I could test this with my existing lenses before even buying a CCTV lens.
So I did the logical thing and experimented to see if it would work before I bought anything. Mount a lens in reverse on a camera and then hold another lens in front of it to see if I can focus any sort of image. All I got was a very good look at the dust on the second lens. I’m either missing something or the whole idea is daft. I do wish I could find the original article.
But in the meantime I have a couple of useful portrait lenses, a very close-focussing portrait lens and a huge glass condensing lens from an old overhead projector. I’ve been playing with the latter by taping it to the end of a cardboard tube. It’s got a focal length of around 330mm but I could shorten that by putting a magnifying lens between it and the camera.
I’ve also got a 9 diopter closeup lens that looks like it might be a doublet rather than a single element, so might be better quality. This particular one has a focal length of 115mm so fills-in the gap between my two projector lenses. The right size of step-up ring should mount this on my bellows. Or this might be the lens I use with the OHP lens to reduce the focal length. Decisions, decisions…
Go me! I’ve got more lenses than a Fleet Street pro (do they still exist?). There are people who pay good money for this sort of fuzziness.