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11-07-2012, 09:01 PM   #31
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JP,

The Fotodiox aperture version I have needed the inside painted flat black for good results with at least one of my lenses.

It is not ribbed inside.

11-07-2012, 09:37 PM   #32
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QuoteOriginally posted by Docrwm Quote
The more I look at the pictures, and I may be way off here, the more the banding looks like an artifact of the ribbing inside the adapter.
Hmmm that sounds like a possibility.

I'm also beginning to think that full frame lenses may be more prone to reflections in these adapters because they project a wider image light circle.
(I think Barondla had surmised that could be the prob.)

Perhaps also some combination of the large image circle and a glass element near the rear that bounces the reflected light back on the sensor?

Perhaps Doc you can try some of your DA lenses on this adapter and see if the banding goes away?
11-07-2012, 09:42 PM   #33
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Mine is the RJ adapter with aperture ring and tripod mount. It is smooth inside- lacking ridges. Aps-c and FF lenses are projecting a much larger image circle than the Q sensor. Newer digital lenses claim to have a special digital coating to reduce light bouncing back and forth between the rear lens element and sensor. Pentax DA*300, 55-300, and DA100 macro show a little less contrast with unpainted adapter. The Sigma 50-500( non IS version) turns into a white haze past about 400mm. It is unusable without the painted adapter.

Bet the Pentax Q-PK adapter will have better internal flocking. This could be with flat black paint, ridges, felt, internal baffles. or a combination of these technics. Hurry up with that adapter Pentax.
thanks
barondla
11-07-2012, 09:50 PM   #34
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QuoteOriginally posted by barondla Quote
Bet the Pentax Q-PK adapter will have better internal flocking. This could be with flat black paint, ridges, felt, internal baffles. or a combination of these technics. Hurry up with that adapter Pentax.
This pic it looks kinda semi-glossy inside, but looks like it is sectioned off. Wonder if this is how the production ones will look.


11-08-2012, 04:46 AM   #35
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QuoteOriginally posted by stormtech Quote
I see quite pronounced banding in your image....
For me, the banding (as shown) appears when my higher contrast subjects were placed near my pc monitor. I surmised I might be picking up some refresh rate flicker from it in the image. I found not using the monitor as a dominant lighting source seems to correct the effect.

Cheers... M

Last edited by Michaelina2; 11-08-2012 at 05:46 AM.
11-08-2012, 05:37 AM   #36
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Original Poster
QuoteOriginally posted by Michaelina2 Quote
For me, the banding (as shown) appears when my higher contrast subjects were placed near my pc monitor, I surmised I might be picking up some refresh rate flicker from it in the image. I found not using the monitor as a dominant lighting source seems to correct the effect.

Cheers... M
Ah, that might well be a part (of all) of the reason here. That was taken image was taken at my work station area at home.
11-08-2012, 09:14 AM   #37
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QuoteOriginally posted by Michaelina2 Quote
I surmised I might be picking up some refresh rate flicker from it in the image.
Good observation Michael.
11-08-2012, 09:28 AM   #38
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I should have mine tomorrow.

11-08-2012, 09:36 AM   #39
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Original Poster
QuoteOriginally posted by Michaelina2 Quote
For me, the banding (as shown) appears when my higher contrast subjects were placed near my pc monitor. I surmised I might be picking up some refresh rate flicker from it in the image. I found not using the monitor as a dominant lighting source seems to correct the effect.

Cheers... M
Tried the same shot, no monitor on (turned off completely), same lens, same adapter, same settings - still have the same banding. I think my surmise about the ridges in the adapter may be the source of the even bands being reflected off one of the ridges surfaces onto the sensor.
11-08-2012, 10:45 AM   #40
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Is the banding also seen using daylight - outdoors and with different lenses?
11-08-2012, 11:14 AM   #41
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QuoteOriginally posted by crewl1 Quote
Is the banding also seen using daylight - outdoors and with different lenses?
I was thinking the same, florescent lighting can be weird.
11-08-2012, 11:20 AM   #42
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QuoteOriginally posted by crewl1 Quote
Is the banding also seen using daylight - outdoors and with different lenses?
Will try those variations next. The indoor light is tungsten not florescent BTW.
11-08-2012, 11:36 AM   #43
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I've recreated the banding with my non-ribbed adapter, so it does seem to point to some type of interaction between the lighting source and the sensor rather than reflections from the ribbing on the adapter.

This shot was lit by my computer monitor. A subsequent shot with an open door as the light source did not exhibit the banding.
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11-08-2012, 12:05 PM   #44
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1/50, I guess you got 60Hz flicker that is up-scaled with some kind of HF-generator for the lighting. I don't have my camera beside me but if I remember correctly there is some kind of flicker setting, is it set to 60Hz? I get that problem when filming aquariums at around 1/50.
11-08-2012, 12:18 PM   #45
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Yes the monitor is set to 60hz refresh rate - the other option for the monitor is 75 hz.
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