Why is my adapted Takumar 200mm lens so soft on a Canon 60D, and can it be fixed?

Asked 7/12/2020

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I’m using a vintage Takumar 200mm M42 lens on a Canon 60D with an M42 adapter. I like the rendering and bokeh, but every image looks soft across the frame. Stopping down from f/3.5 to f/22 doesn’t seem to improve sharpness. The glass looks clean with no fungus, oil, or scratches.

Example conditions were daylight, handheld, ISO 640, around 1/8000s, though the adapter does not record EXIF correctly. Even areas that should be in focus still look soft when viewed closely.

My Canon lenses on the same camera look much sharper. What could cause this kind of softness with an adapted vintage lens? Is there anything I can check or fix? Would using the lens on a full-frame camera help?

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

Photography Stack Exchange contributor

6y ago

2 Answers

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Any number of issues with an adapted lens can be the issue with perceived softness.

  • The lens itself may have a decentered/loose element. There may also be element separation, or other issues. M42 lenses are typically 40-50 years old and can be hard to find in good operating condition.
  • The adapter could be too thick/thin for proper focusing.
  • Trying to judge critical focus through the viewfinder is harder, because of stop-down metering, and the fact that there are no manual focus aids in modern digital-era viewfinders which are optimized for autofocus.
  • The sensor stack over the sensor could be causing issues (although that's more of an issue with mirrorless cameras).
  • Using distance scales and DoF scales on the lens to zone focus may be inaccurate, as those are for full-frame, not crop.

There may not be much you can do other than to get the lens serviced/checked out, possibly try a different adapter, and to use a tripod and do critical manual focusing with the LCD and liveview + magnification or focus peaking.

Originally by user27440. Source · Licensed CC BY-SA 4.0

user27440

6y ago

0

AI Answer

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

Several things can cause softness with an adapted vintage lens.

Most likely possibilities are:

  • the lens itself has an optical fault, such as a decentered or loose element, or element separation
  • the adapter is not the correct thickness, which can throw off focus
  • focusing is inaccurate, since DSLR viewfinders are optimized for autofocus and manual focus is harder, especially with stop-down metering

Because M42 lenses are often decades old, clean glass alone does not guarantee good optical alignment.

Stopping down should normally improve sharpness, so if it does not, that points more toward a lens or adapter problem than normal wide-open softness.

A full-frame camera is unlikely to magically fix it. It may actually reveal more issues near the edges. Also, distance and depth-of-field scales on the lens were designed for full frame, so they are less reliable on your crop-sensor 60D.

Best checks:

  • try a different M42 adapter
  • test on a tripod with careful manual focus, ideally using magnified live view if available
  • compare center sharpness at several distances and apertures
  • if still soft everywhere, the lens likely needs service or is simply defective

So yes, it may be fixable, but only if the cause is focus technique, adapter tolerance, or repairable lens misalignment.

UniqueBot

AI

6y ago

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