Where are these points in these photos ?

Started Dec 17, 2013 | Questions thread
fotowbert
fotowbert Senior Member • Posts: 2,890
Adaptor reflection fix

ProfHankD wrote:

hannu h wrote:

Those artefacts in the sky. I tried by zooming towards sky. No sun here in this time of the day. With Md 50/1.7, and yashinon m42/1.4, hexanon 50/1.7, cirlcles were less visible than in canon. I have another fd adapter and when I tried it in fd 50mm, it seems to be better.

In the first Canon adapter stopping down made all worse. Yesterday I ordered third cheap fd adapter, hope it is not same as thiis worse one. I made an order before I noticed this artefact thing.

Flare can come from anywhere along the optical path. Something shiny inside your adapters? Stopping down will often worsen reflection problems like that (by increasing contrast, bringing reflections closer to in-focus, adding reflections off worn aperture blades, etc.).

If so, a black permanent marker might make a difference.

The circular artifact is likely the result of a shiny surface facing the sensor inside the adapter probably the adapter itself but do the inspection below with the offending lens attached in case it is also contributing.

Looking into the rear of the adapter with the aid of a small flashlight held at different angles watch for any feature that reflects the light beam back to you. Even black coated surfaces will reflect when smooth.  In this case I would expect it to be a narrow circular feature perhaps even just a sharp edge.

Many black markers don't dry to a dull finish on a smooth surface. If that turns out to be the case then a "flat" black paint (model enamel from a hobby store) could be tried.  Getting paint to stick to slick surfaces, especially raw aluminum, can be a problem. The last thing you want is paint flecks loose inside your camera so test it on a small spot and see if it can be easily dislodged when fully dry.

  • John
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