What are the drawbacks of converting Canon FD lenses to EF mount for DSLR use?

Asked 2/24/2014

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I’m considering converting older Canon FD/FDn lenses to Canon EF using a replacement mount such as an EdMika kit. I understand the converted lens would be manual focus and manual aperture only, but FD lenses can be inexpensive and appealing for portraits or video.

Aside from losing autofocus and electronic aperture control, what practical downsides should I expect when using converted FD lenses on an EF DSLR? I’m especially wondering about image quality, viewfinder/focusing usability, and any mirror-clearance or compatibility issues on full-frame bodies.

Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0

Photography Stack Exchange contributor

12y ago

2 Answers

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Since you also mention video, I assume you want to mount them on a DSLR.

It's not pointless (especially given the saving), but... the result might not be what you expect. This depends of course on the quality of the lens : an excellent one could still perform quite correctly. And maybe tack sharp is not what you need, depending on your artistic aims.

I'll try to sum up the possible issues with using older lenses on digital cameras.

  • The imaging sensor is more reflective than the surface of film used to be, which is compensated in newer lenses by an extra coating on the back, that older lenses don't have. So image contrast can be degraded.
  • It was not true some time ago but now 20+ megapixel sensors are much more discriminating than film
  • Some optical formulas, as well as glass performance have evolved, so you might find a current lens with equivalent performance... at the same price (or cheaper on second hand)

Originally by user26278. Source · Licensed CC BY-SA 4.0

user26278

12y ago

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AI Answer

Generated from our catalog & community — verify before relying on it.

Converting FD to EF can work, but there are real tradeoffs.

Main drawbacks:

  • manual focus and manual aperture only
  • DSLR viewfinders are not optimized for manual focus, so accurate focusing can be harder than expected
  • stopping down darkens the viewfinder, which makes focusing/composing harder at smaller apertures
  • some FD lenses may have rear-element or mirror-clearance issues on certain full-frame EF DSLRs
  • older lenses may show lower contrast or more flare on digital sensors, partly because digital sensors are more reflective than film and newer lenses were designed/coated with that in mind
  • high-resolution digital sensors can reveal the limits of older optics more clearly than film did

So it’s not pointless, especially if you want a particular rendering for portraits or video, but the results may be less sharp or lower in contrast than you expect depending on the lens.

If you mainly want to adapt old FD glass, mirrorless bodies are usually easier because their shorter flange distance often allows simple adapters without mount replacement and avoids DSLR mirror issues.

UniqueBot

AI

12y ago

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