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-   -   canon 400d spots (https://www.worldphotographyforum.com/showthread.php?t=3616)

willba 07-09-08 22:58

canon 400d spots
 
Hi everybody
Hope somebody can help, when I look through the view finder I see lots of little spots I thought it was dust on the senser but when I look inside it appears to be on the mirror,unsure how the mirror works with senser so I dont know if thats what it is, Ive had a magnify on the senser and it seems clean, so would the dust on the mirror be seen through the view finder,
any help would be grateful

Will

gordon g 07-09-08 23:13

The view through the view finder in any type of slr, digital or film, is an entirely optical pathway, ie through the pentaprism, and out through the lens via the mirror. The sensor doesnt come into it. The spots are therefore likely to be on the view finder glass, possible the focussing screen (the bit of glass in the roof of the shutterbox above the mirror) or mirror, or on/in the lens itself. A systematic check of these should sort your problem out.

willba 07-09-08 23:54

many thanks gordon g
Is that why the spots are not on the images when I print,

gordon g 08-09-08 00:17

If they arent on prints, but are visible through the eyepiece, then they are after the sensor in the visual pathway. Ie, not on the lens (which would be seen by the sensor), not on the sensor, which we know already, perhaps on the mirror or focus screen, most likely on the view finder glass.
Spots would only appear on the prints if the sensor could see them.

miketoll 08-09-08 14:49

Agree with Gordon, if the spots are in focus then they are on the focussing screen so are merely annoying and will not affect the picture. Try a gentle puff with a blower. ie bulb blower.

sassan 09-09-08 04:09

Simplest thing you want to do, to differentiate, is to take a picture with very narrow F stop say 32 22 if your tele or macro lens has one or at least 16 that any lens has. Subject is a lighted uniform color; say sky. Even if you have low shutter speed, it doesn't matter.
The sensor dust, scratch will shine up at this point. If you see nothing, have a deep breath. It is dust over mirror or on pentaprisoms surface etc that does not interfere with your image as that is the line of sight for eye, and not the line of capture on sensor.

willba 11-09-08 22:34

Hi everybody again
I have found were the spots are, they are on the plastic or glass I dont know what it is made from where the focus spots are above the mirror, I have now cleaned it almost gone, I dont know were it came from but its a lot better now,
Many thanks for all your help. Will

miketoll 12-09-08 12:20

These little bits get in when you change lens. Glad it is fixed now as although it does not affect the picture it is so annoying! If you do ever get spots on the mirror they will be out of focus and remember the mirror assembly is delicate. If you can see marks on the photo that means the stuff is on the sensor which is another ball game so ask again if in doubt what to do when it happens as it inevitably will!


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