Canon DSLR on 4×5 Camera

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This morning I happened to remember something that happened over two years ago and I thought I might share it.

I had just purchased a 4×5 monorail camera with all the adjustments. The idea was to have a nice landscape camera and attempt all those neat things the camera was capable of. After getting a couple of LF/MF lenses and making lens boards to fit the camera, I realized that I was not at the time able to do B&W chemistry in my basement. 

On eBay I found a source in Hong Kong for a film holder with an EOS attachment. Wow ! All I had to do was connect the camera to the film holder, attach it to the camera and I was golden ! Wrong ! Wrong ! Wrong ! Wrong ! I wish I had simply done the math ahead of time. As I remember, the adapter was +$100USD plus shipping.

I first tried out the 400mm MF lens with my Rebel 300D DSLR with a crop factor of 1.6 versus a normal 35mm film camera. After realizing that what I was seeing was a super telephoto image, I sort of sat back and tried to figure out what was going on.

4×5″ = 12827 square mm area. 22×15mm APSC sensor = 330 square mm. 12827 divided by 330 = 39. Thus the area of the image captured by the APSC sensor is 1/39th the size of the image for a 4×5″ negative. So, the 400mm lens would equate to a 15,600mm lens. Not exactly a winning image size unless I was going to work for the CIA. Even if I used an EOS film camera the factor would be 1/15th, not as bad, but still not readily usable.

If the images were spot on – tack sharp I could have had some jollies with it. Unfortunately, the need to step the lens down in order to get some depth of field caused the images to be dark. Secondly, they were never sharp as I would like, I believe this was a combination of the mirage effect of the air and the inability to pin the camera down with no movement short of parking my car on it. The angle of view of a Sigma 400mm lens according to their website is 6.2 degrees. Divide this by 39 and you get .1589 degrees, so any movement of the object or the camera will show.  

Needless to say, the adapter has been sitting in a drawer since that first day. Even if one were to take a 40mm MF lens, it would still be equivalent to a 1,560mm lens. Perhaps, I will someday find a need for such a combination, and be glad I have the ability…… maybe …..

Disclaimer: All the math is done with the intention of showing understandable comparisons with no attempt to nit pick over super accuracy.

CLICK HERE FOR FURTHER ADAPTER INFORMATION ON MY BLOG

Double Slit Camera 4

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The super lens cap is finished, tested and a new page containing photographs has been created.

Double Slit Camera 3

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This morning I got what I needed together for this project. As I mentioned before, I have turned aside a bit from making a whole camera in order to determine something of the physical characteristics needed. This will be a lens cap on steroids, so to speak. I am using a set of macro rings as the basic structure, single edge injector razor blades for the slit edges, black core foam for the blade holders and information I have gleaned from the internet. If the findings are OK, I will then turn to making it in a 4×5 MF wooden camera with a Graflex roll film back using 6×7 negatives.

A few words here on the internet information – there are many references to slit cameras, however, most are related to either cameras used to determine finish line winners or the very interesting experiments on quantum physics showing how light travels as both waves and particles depending on whether they are being observed or not – real SG1 tech talk, huh ? Try this for a starting point – you will start wondering when the Asgard are going to beam you aboard – I hope you have on clean undies – LOL.   http://fr.youtube.com/watch?v=usTOM8vffB4 or search the internet for>> Dr Quantum <<

 Further, the little related to what I am doing is mainly of the sort “I am going to make a double slit camera and I am all ready to make it, and it is going to be neat. Can anybody give me information on how to do it?”, or, “Here is a link to (pictures, information, guidelines, etc)”; a vast majority are either dead or not having anything related to the subject. The three places I did find that had needed information are enough to get going, I will either place the information or the links on my www.photographyhacks.org website after I actually determine if they are worthy.

So, here I am saying I am going to do it AND post pictures yadda, yadda, yadda ……….  Well, I do have good intentions of doing just that and you can determine if I follow through by checking back here for updates. Below is a quick picture of my worktable all set to start.