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How to degrade an image in-camera to simulate Old Spyglass


Joe Taylor
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I'm going to be filming a scene for a western where a character is being pursued on a dry lake-bed where those giving chase are perhaps a half-mile behind. The lead character pulls out an old spyglass to gauge their position and I want to degrade the image and make it both interesting and realistic and I want to do this all "in-camera." I'm likely going to stack some old filters, (one is a pitted Black ProMist and the other is a 4x5 filter I made from a 150-year-old window. I'll likely use an old Canon FD telephoto zoom at f22 @ 100mm. This added depth of field will make the debris on the filters more pronounced.

 

Can anybody suggest anything else I can do to scuzz up the image to make it interesting? I've even thought of putting a thin coat of greenish motor oil with flakes of hair and other stuff, but I could be taking this too far by doing that.

 

Love to hear some suggestions. Should be fun.

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Get some very cheap, thin diffraction grating material and cut a ring out of it to just go around the inside 1/4 of the lens; a doughnut shape. Might have to experiment with ring thickness and edge roughness to make it subtle enough. Shouldn't take much...

 

https://www.amazon.com/Sheets-Diffraction-Gratings-Lines-inch/dp/B07D9K1582/ref=sr_1_14?ie=UTF8&qid=1538970309&sr=8-14&keywords=diffraction+grating+sheet

 

That should give you some weird aberrations...

 

Maybe you could remove the front lens element and find an arrowhead maker to knapp the element; chip it up on the edge and then replace it. Not hard to remove those front elements...

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It would be nice to find a way to get a lot of chromatic aberration and edge softness... dont know if it would focus properly if shot though a magnifier glass or if you put two diopters together, one backwards to cancel the first one, etc.

The idea's good, but a dioptre is still a dioptre backwards- think of a magnifying glass. Works both ways.

Maybe a weak single-element dioptre that's a bit too small for the lens so it vignettes. Or just the bottom of a bottle.

It's not going to help to say that optics could be quite decent 150 years ago, is it!

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Why not build your own lens?

 

There are some ideas here:

https://www.diyphotography.net/build-your-own-lenses/

 

Some simple lenses $5-$20

https://www.surplusshed.com/search_lenses.php?type=&diameter_to=&diameter_from=&focal_length_to=100&focal_length_from=500&sort=type_search&sortby=+asc

 

mount the lens in some telescoping plastic or cardboard tubes. If it vignettes, all the better! If it's just a few shots, you could even tape the contraption to the camera lens mount.

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It would be nice to find a way to get a lot of chromatic aberration and edge softness... dont know if it would focus properly if shot though a magnifier glass or if you put two diopters together, one backwards to cancel the first one, etc.

I have an old Canon zoom that I can 'Frankenstein' with the elements. I have a couple of weeks to try something.

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Get some very cheap, thin diffraction grating material and cut a ring out of it to just go around the inside 1/4 of the lens; a doughnut shape. Might have to experiment with ring thickness and edge roughness to make it subtle enough. Shouldn't take much...

 

https://www.amazon.com/Sheets-Diffraction-Gratings-Lines-inch/dp/B07D9K1582/ref=sr_1_14?ie=UTF8&qid=1538970309&sr=8-14&keywords=diffraction+grating+sheet

 

That should give you some weird aberrations...

 

Maybe you could remove the front lens element and find an arrowhead maker to knapp the element; chip it up on the edge and then replace it. Not hard to remove those front elements...

Those are really cool! Great idea!

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Hate to say it.. but what about post effects .. thats going to give you the most freedom in image manipulation .. and make it alot quicker to shoot it on the day.. there are millions of effects out there now that takes a couple of seconds too apply..

I'll use post with a clean shot as a Hail Mary.

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I'll use post with a clean shot as a Hail Mary.

 

Im not against doing things in camera.. as an old dog I used to be totally for it.. but now I have filters that I hardly ever use.. After seeing the finished product, younger directors have shown me thats these days "I,ll do it in post" is not the devil talking..and a slow slipping into the depths of Hades .. but mostly totally the best way to achieve the look they want .. although still get the occasional director shining a torch down the lens or waving bottles in front of it.. :)

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You could try using an old zoom lens, decollimate it drastically relative to the mount by removing or adding shims which are often found between the mounting tail of the lens and lens body. Finding focus will be interactive with the zoom movement and you may find the edge of the image goes off focus or weirds out in some way. Make sure you do not lose any shims so that you can restore the lens later. As mentioned above, optics in the olden times were not perfect. Until a very recent theft, I had an old pair of binoculars dating from about 1910 of a non-prismatic design which yielded a clean image to the eye. Old optics are often degraded due to age and no longer representative of their original image quality.

 

You might otherwise try a leaf out of the old 35mm groundglass adaptor book and shoot the aerial image from another lens in front of your camera's own lens. To achieve chroma abberation, edge softness and even coma ikn the edge as a bonus, you would use the cheapest single element screw-on close-up lens you can find and stack the for 7+. You could get away with 4+ but your forward offset which I mention further along this response would need then to be about 7 or more inches ( approx 800mm ). The method is awkward and unwieldy. You would attach a 7+ close-up dioptre lens to the front of a camera lens of about 100mm focal length for a small sensored DLSR, the smaller the front element of that camera's own lens, the better. Then position the tail of another lens about 6" or 150mm in front of it and aquire the aerial image of that lens in front which will need to have a large exit pupil, think 20mm wider or more. You will need to make a lightproof enclosure or your image will be contaminated by ambient light. To set up, your aerial image plane, you will use a small paper target with some marks on it. Move this forward of your camera with its lens and close-up dioptre until you have a clear image. The position the flange face of your other lens in front a further 44mm forward if it is Canon, 46.5mm further forward if it is Nikon or 52.0mm furthur forward if it is PL-Mount. When you remove your paper target you will be in the ballpark of aquiring an aerial image through the lens in front. That image will appear upside-down. Depending upon the size of the exit pupil of that lens you will get a vignette which may or may not be manageable. Ff you have the front lens focused for close-up and moved slightly rearwards to restore sharp focus on a distant object, then there will be a definite edge defect in the image and likely a vignette from the iris as well if you close it. Whilst I have some regrets at dismantling old equipment, an old groundglass relay adaptor like a Letus35 Extreme or Ultra can be used in aerial image mode with the groundglass removed. You need however to use the camera type for which it was built which usually means 1/3" sensored cameras and a focal length setting on that camera's own lens of about 60-70mm. The relay lens and mounting ring on the back of the Letus is also specific to camera type. With an erecting groundglass adaptor like Quyen and Hien Le's Letus, Dennis Wood's Brevis and Wayne Kinney's later SG Blade designs, the groundlgass panel is relatively simple to remove after the adaptor's front case is opened up. A P+S Technik Pro35 is suited to 2/3" sensored cameras but removing the groundglass is a real mission and likely to be destructive. There have been a few experiments with large format plate cameras by either filming the screen image of a large 6" groundglass plate or bouncing the large format lens image with a mirror forward onto a reflective screen within a lightproof box and photographing that reflected image.

 

You would find this very bulky and awkward.

 

My personal preference might be to use post effects as suggested in previous responses above.

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This linked clip of rather poor HDV quality was shot using a Sony HVR-Z1E, a 4+ power close-up lens for relay and a home-made AGUS35 adaptor with the groundglass removed for aerial image and a Sigma-for-Nikon 50mm - 500mm zoom attached on the front. The aerial image typically has a lower contrast and more often than not picks up the edges of the iris in this arrangement. It was with the available tech of those times, the only affordable long reach option for me at the time.

 

 

 

Here is a link to a home-build AGUS35 groundglass device being dismantled to give you a sense of the principle. In this instance it is an image-erecting or "image-flip" arrangement with a prism pair. For your purposes that would not be a complication you need to have to deal with.

 

 

 

Here is a large format arrangement which uses a plate camera, a Nikon DSLR, a macro lens which eliminates the need for a dioptre and a groundglass. This arrangement is unlikely to work in aerial image mode due to the wide angles of view of the optics and the projected image but who knows? In this instance, the builder has used a fresnel "condenser" lens in the path between the front lens and the groundglass to eliminate the vignette defect you may will be looking for. The "Coatwolf" camera used for the independent film "Bellflower" was a similar arrangement except the used was one of the early SI2K camera heads.

 

Edited by Robert Hart
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I found myself yesterday needing to use a magnifying glass to read some very small print. After I finished I held it up and projected the image of my ceiling lamp onto a piece of paper. I saw lots of blooming and focus fall off and the lens seemed to have a focal length of about 135mm (just guessing), but it seemed just the right thing to use.

 

So, maybe just go to the local office supplies store and get one. Then go to the plumbing store and find some plastic pipes to make a telescoping spyglass and just tape it to your lens mount and give it a shot. You might want to add some ND gel inside to get keep the exposure in check if necessary. Yes, it will take you a few tools and an afternoon to build this thing, but very little money.

 

If the lens is not telephoto enough for you, add a 2nd magnifying glass lens to the contraption.

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The magnifying glass suggestion is probably as good as any to try. You will be of course to use ND filters and shutter speed to control the light because as a camera lens, its aperture is wide-open. Once you have established the point forward of your camera's lens mount where sharp focus occurs from the magnifying glass to your camera's sensor, you may be able to control light with a simple round aperture hole tidily cut in a thin piece of card positioned between the magnifying glass and the camera. you will need a lightproof enclosure around the magnifying glass and the path between it and the camera.

Edited by Robert Hart
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Wow, Robert Hart. There's a world of info in those posts and I'm very appreciative. I'll go through them again tonight when I get home to try and glean some of the 99% of what went way over my head just now.

 

I had thought about doing trying to get a shot using the ground glass off an old 4x5 speed graphic, but it needs to be telephoto.

 

There's a lot of good ideas and suggestions all around. Another reason I want to try and do this all "in-camera" simply because it's fun and I have the time before we shoot on the 23rd. But I will shoot a couple of takes that are clean in case I can get more realistic results in post. The one thing I am not after is something that looks stupid, which is what often happens when people take too firm of a stand.

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