Markus Hofstaetter's blog » projection lens

Thursday, August 3rd, 2023

Should you buy a scratched lens?

This topic brings often lots of emotion up. And honestly I was struggling myself buying lenses with scratches for some time. I still do. Thats why I wanted to take a closer look into this topic . Gary sent me a scratched lens some time ago and therefore made this video possible. Thanks a lot for that!

This old Ross projection lens got lots of fungi and scratches all over the glass

But this is not the first scratched lens that I got, I bought a used canon 24mm lens a while ago from a shop for very little money. I knew already that the little scratches will not affect the image, but I still had a bad feeling. After Some years I can assure you, that all images that I shot with it looked great

my scratched canon 24mm lens – no issue at all to work with it

You still are not sure if you should get a scratched lens for a good price? Then have a look at my video, where I show how I shoot the plates with a scratched lens. I discuss this topic with a fellow wet plate artist who is also a specialist in renovation of historic photographic equipment: Denis of Denis started recently a YouTube channel where he spreads his knowledge of historic lenses.

As promised I posted the hires scans of the plates underneath. One plate is shot with the old Ross projection lens and one is shot with this very new Zeiss Epic projection lens.

This projection lens is as clean as it gets

Can you guess which plate was shot with the scratched lens? Click on the highres crops to see them in full resolution. You can use the chapters of the video to chump to the part where I explain what plate was shot with the scratched lens.

Shooting wet plates with this projection lenses can be very tough, because the dof is very thin. I also think that one of the lenses had some chromatic aberration. That means, that the blue light is focusing on a different distance than the visible light. This is sometimes also called chemical blurring or chemical miss focus with the wet collodion process, because the wet collodion process sees only some parts of the UV light spectrum (about 420 to 490nm).
I can only focus on the light I can see with my eyes, but some lenses focus because of the chromatic aberration the limages for wet plates on a different spot. Thats how a miss focus can happen. But you can see how extremely sharp both lenses performed anyway. To judge the sharpness for image A, have a look at the top and the right side of the cropped scan.

Even I knew what was the plate that was shot with the scratched lens, and I still mixed them up and was convinced I was right when I showed it to my intern, shows how similar the plates are. This was another point that went to the scratched lens. Scratches and fungus mostly cover only a small percentage of the lens and thats the reason it won’t affect the image that much as you would think.

If you want to support me and get deeper into topics like that, you always can book a workshop or join our Patreon team. Or just book a portrait session . Check also my Instagram channel for latest news:

So what does that mean, should you buy scratched lenses? From our perspective, you definitely can buy scratched lenses. You will save money and still get the same results. It only affects the value. As always, it depends how big the damage of the lens is. More about that in my video. If you buy lenses as an investment, you probably will look for a mint lens, but here you have to put lots more money on the table.
At the end, it all depends on your needs.

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  • Posted by Markus | Filed in alumitype, analog, nassplatte, wetplate, workshop | Comment now »


    Wednesday, May 10th, 2023

    Shooting a HDR tintype with a super fast lens (and get them on Ebay)

    When shooting wet plates, you deal with a very light insensitive process (about iso 0.5). So most wet plate artists wants to get their hand on a fast lens. Wolfgang, a former participant of my wet plate workshop got his hand on a very fast lens and sent it over to me. For the first time, you can get the plates from this project on eBay, starting from 1 Euro –

    tintype portrait of Wolfgang
    Wolfgang, an Austrian based photographer who made this video possible – thanks a lot!

    This Delta HD-6C ML lens is pretty huge and was used in vintage HD protectors many years ago. If you want to know more about this kind of lenses, check this blog post:

    Here you can see how big this monster (a Delta HD-6C ml) is compared to a 35mm film canister. At the bottom you can see my self designed lens mount that I printed. A “very professional” 😉 solution.
    A professional lens mount needs a “professional” lens support. For that I used plate holders and other stuff that was laying around in my studio. I looks a little bit like a Frankenstein monster build. But it grew on my and I like it that way.
    The dreamy outcome with this wonderful bokeh makes it to my new Bokeh Monster

    See the full transformation in my video

    The yellow part of the flower absorbs a lot of UV light and thats the reason it appears dark when I exposed the plate normally. Thats why I did this series of 4 different exposures. I think every single one of them has something special in it. Just for fun, I created a digital HDR image out of them

    Silver and light. Four exposures that are very different.
    My digital HDR conversion of the tintypes. Next time I will try a combination of glas and metal.
    I love this one a lot and will have a hard time to let it go on Ebay
    If you hold this 18x24cm tintype in your hand, you can see the sling of all the little silver particles. This plate of this series will go to one of my Patreon supporters. Join here, if you want to be part of the raffle as well, join my supporters here:
    This lens has a razor sharp depth of field and therefore it’s not easy to handle. But if you get it under your control, you can archive unique and very dreamy results. I look forward to use it again.

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  • Posted by Markus | Filed in 3d print, alumitype, analog, collodium, Gear, tintype | Comment now »


    Wednesday, March 22nd, 2023

    Traveling with an Ultra Large Format Camera for a Wedding Wet Plate

    With todays video I want to give you a glimpse how it is to travel with an ultra large format camera. This time I didn’t bring my darkroom tent, because I could use the shop on the farm. Traveling with my big camera is always a hassle and can bring some troubles with it. But this time it worked out great.

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    Wednesday, March 8th, 2023

    Shooting an ultra fast lens (140mm F1.0) with an ultra large format camera

    In short words “this lens is something else”. It’s extremely fast, huge and has a strange focus distance. It was used in Sony CRT Projectors from 1997. I bought it some years ago from a very interesting guy. He had so many more great stuff in his shop and I regret that I did not buy more. It took me some time to find the right opportunity to use that lens. But I think it was worth the waiting. I am glad my friend and former workshop participant Alois Stingl came over with is wonderful ultra large format camera.

    Before I could use it, it needed some cleaning, I used a cloth that was soaked with water and just put it on the lens without wiping to avoid more scratches.

    with some patience I could clean it.

    I measured the lens at infinity to calculate the F-Stop. I measured 135mm and the front element was 145mm That is about a F0.9 lens. But a document I found on the internet told me its more an F 1.0 lens. Still crazy fast.

    You can see here how short the focusing distance is. That makes it hard to focus un an ultra large format camera.

    When I saw the yellow coating on the front element of the lens, I thought about Mathieu Stern’s video about radioactive lenses. If it really is made of Thorium, it is indeed radioactive, but only for a very small amount. Watch Mathieu’s video to learn more about this Material

    Thorium was used to get more light into the lenses back then.

    Because the lens is very fast it is still dangerous. If it focuses the sun on something, it will start to burn immediately. That’s the reason you should not put the lens near a window and always put a lens cap on it.

    In the video I will show you how easy you can start a fire with that lens

    I thought it would be interesting to calculate the crop factor of an 40x50cm ultra large format camera. If you use the common formula to calculate crop factors you will see that this plate size has a crop factor of 0.0067 compared to a full frame sensor. With that you also can calculate the comparable depth of field F-Stop. This would also be F 0.067 compared to F 1.0 on a full frame camera. When I tried to focus on the ground glass, I could barley find something in focus. Thats why you see me focusing for a very long time.

    it took quite some time to focus with this very fast lens.
    I think this shows pretty well how sensor and plate sizes compare

    But there is more. a 140mm lens is a tele lens on a full frame camera, but it’s a wide angle lens on an ultra large format camera. This is because of the bigger plate size of the ULF camera. listen to my full explanation in the video.

    My drawing shows in a simple way that the subject needs to be farer away from a full frame sensor the get the same angle of view as the close setup of the ULF camera.

    To “connect” the lens to the camera, I designed and printed a basic flange in Tinkercad. It needed some pool line and tape, but eventually it worked out.

    I think Tinkercad is one of the most yeas to use tools for 3D printing.
    a very basic part, but incredible helpful
    No screws, just tape, pool liner and my 3d print. Sounds funny, but worked wonderfully

    The next issue was the fact that my darkroom was not made for 40x50cm plates. only for 30x40cm ones. After some tests with smaller plates, we only had one cup of developer left. Beside that, everything starts to get unpleasantly expensive if you pour on plates with this size. So my goal was to make it work with only one attempt. I did some dry runs to get comfortable with everything. Not only the dark room work was something I had to prepare for, but also the camera. These old beauties all have some quirks. Besides that, Alois made a beautiful plate holder by himself. These holder needed also some special attention. But as explained in the video, I love these challenges. It makes the result at the end even more sweet.

    To calculate the strobe power I needed, I used my wet plate strobe calculator that I created for my Patreon supporters. Since I made it, I use it all the time for myself, because it makes life much easier with the wet plate process. If you are a fan of analog photography and the wet plate process, have a look at our wet plate conversation magazine on Flipboard. Besides many great stories about our favourite process, you’ll wind there also work from other wet plate artists.

    I really like how this portrait turned out. As expected it is very abstract because of the F-Stop and the wide angle lens.Here you can see again how huge that tintype is.

    But this is not the end, because of some kind of funny coincidence, a former workshop participant sent me a very similar lens over. I am thinking to do a still life plate with that one. What do you guys think?

    Two very similar lenses. Funny how sometimes things turn out.

    But there is more, I got also a very tiny lens. I guess I need to build a camera for this one

    A full functional lens in the size of a thumb. I haven’t seen such a thing before. What a cutie.

    I hope you enjoyed that journey. It took me a long time to finish everything, but I am again glad that I worked through it.

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