Canon FD Bellows on 5D

[photo-vinc]

Hello,

I am selling my FD system but I did decide to keep bellows and marco lenses. My plan is to use them with an adapter on the 5D.

I purchased an adapter (make: Kood) which has a lens in it. This lens which compensates the extra distance caused by the adapter, is not best quality optics I suppose.

My first approach was to remove the lens, which is not needed when using bellows. Optical this is the best solution but a better aproach came into my mind.

Drawback of removing the lens is sensor dust. Moving the bellows will blow dust on the sensor, there will be high amounts of dust in the bellows since I do not live in a clean room.

I proposed to mount a piece of non magifying glass in the adapter. I already packed the original lens to see an optician when it came into my mind that glass for glasses probably has some coating.

What is the best place to get clean optical glass?

Best Regards,
Vinc

www.photo-vinc.com

[situgrrl]

My first approach was to remove the lens, which is not needed when using bellows. Optical this is the best solution but a better aproach came into my mind.

Drawback of removing the lens is sensor dust. Moving the bellows will blow dust on the sensor, there will be high amounts of dust in the bellows since I do not live in a clean room.

www.photo-vinc.com
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You could get the bellows cleaned and then store then in a zip loc baggie when not in use....

[Nigel Johnson]

What is the best place to get clean optical glass?
www.photo-vinc.com
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Have you considered using the glass from a good quality clear filter such as the Hoya Protector filter ([a href=\"http://www.intro2020.co.uk/pdf/Hoya.pdf]Hoya Filter Brochure[/url]). I believe that the Hoya Protectors are available in sizes from 27 mm diameter up. It should be relatively easy to remove the filter from its mount if necessary; it may be easier to fit the filter still in its mount but this depends upon the detailed design of your converter which I am not familiar with.

I would however add a caution about using a flat glass as you may get problems with lens flare and ghosting off axis, particularly from bright lightsources, because of repeated reflections between the parallel glass surfaces and the reflective sensor (much more reflective than film). Some super-telephoto Canon lenses used to use flat protective elements and generally they have been modified with meniscus protective elements to prevent such a problem (see section entitled "Improving Compatibility of EF lenses to Digital Photography" in the following Canon Technical Report). I believe that they have also changed the rear element of some lenses where it was a flat protector or a plano- concave or convex lens (can't find correct link). The effect is likely to be greatest with an uncoated sheet of glass and should be reduced by using a multicoated filter as your glass (see Hoya brochure link given earlier).

I hope this may be of some help.

Regards,
Nigel