p.1 #1 · Is This a Spot on Sensor, or A Sun Spot on Sensor
I always thought that I was careful, but maybe not. I can’t clean this sensor (A7CR) and I’m wondering what to do next. Do I send it to Sony to clean, or have the sensor replaced? This image was produced at f/16 while aimed at a white chair and using pixelshift to produce 16 files. Files were combined using PixelShift2DNG. This was hand held, so the spot is clearly on the sensor…or sensor cover. I used the sliders in Lightroom to make the defect more apparent.
p.1 #2 · Is This a Spot on Sensor, or A Sun Spot on Sensor
Certainly appears to be sensor dust or a "spot", but why are you saying you can't clean the sensor? Are you under the impression you shouldn't clean it, or have you tried and not been able to clean away the spot?
p.1 #3 · Is This a Spot on Sensor, or A Sun Spot on Sensor
MMP wrote:
Certainly appears to be sensor dust or a "spot", but why are you saying you can't clean the sensor? Are you under the impression you shouldn't clean it, or have you tried and not been able to clean away the spot?
I’ve gone through four sets of pads.. always one wet and one dry… using both sides of each pad and this will not come off. My first time not being able to clean the sensor. I mention burning only because I can’t clean and it appears round, but I just can’t imagine having the sensor face the sun without motion and burning the sensor.
p.1 #5 · Is This a Spot on Sensor, or A Sun Spot on Sensor
bwcolor wrote:
I’ve gone through four sets of pads.. always one wet and one dry… using both sides of each pad and this will not come off. My first time not being able to clean the sensor.
That's really unfortunate. Using the same method, I've been able to clean quite a few sensors that looked far worse. Most of the local camera shops are using the same method so personally, I'd send it away to Sony and let them try. If/when the next cleaning doesn't work, at least it's already with Sony for them to complete the needed repair/replacement.
p.1 #8 · Is This a Spot on Sensor, or A Sun Spot on Sensor
Erictator wrote:
Is it my imagination or is there a ghost of a second identical size/shape spot forming directly below it at the bottom edge of the frame?
Eric
Yes, I see that, so am I imaging the aperture blades or a confused combining of 16 images?
p.1 #9 · Is This a Spot on Sensor, or A Sun Spot on Sensor
If it's a spot on the sensor cover glass it will change size and shape as you change to f/# of the lens.
If you have damaged the sensor the spot size and shape will not change.
Take a series from wide open to f/22 and see what happens. You should not need to use pixel shift.
p.1 #10 · Is This a Spot on Sensor, or A Sun Spot on Sensor
Traditionally testing for dirt is done at f/16 or f/22 against a plain (white) surface. Why are you going through 16 images at a time to test this? How about just doing a test in .jpg? Do you actually SEE a spot on your photos or only when doing this test?
It does appear to be very round,which is not usual for dust, so it may be a sensor defect. Best to send it in for Sony to check, especially if wet cleaning has not helped..
p.1 #11 · Is This a Spot on Sensor, or A Sun Spot on Sensor
PhotoTeacher wrote:
Traditionally testing for dirt is done at f/16 or f/22 against a plain (white) surface. Why are you going through 16 images at a time to test this? How about just doing a test in .jpg? Do you actually SEE a spot on your photos or only when doing this test?
It does appear to be very round,which is not usual for dust, so it may be a sensor defect. Best to send it in for Sony to check, especially if wet cleaning has not helped..
Lazy, forgot that it was set to pixelshift. I agree, the shape makes cover glass smudge unlikely..
I think that sending it to Sony sounds like the best advice and to answer the previous question, I haven’t noticed this with regular shooting, only when stopped down copying negatives.
p.1 #13 · Is This a Spot on Sensor, or A Sun Spot on Sensor
tsdevine wrote:
Does it do this will all lenses?
Yeah, I will try a different lens first. Looks to be too large for oil spot on the sensor, and if it did not change after wet clean. Chip damage is usually not round. And burn will usually be individual dead pixels or small clusters.
p.1 #14 · Is This a Spot on Sensor, or A Sun Spot on Sensor
Why in the world would you use pixelshift and combine 16 files to check for dirt on the sensor?
A single exposure of a white or light colored surface, close to that surface, with the focus set at infinity (so the surface will be totally out of focus) should do it. I usually use the smallest aperture available, to accentuate the spots, but any small aperture (like the F/16 that you used) will work.
p.1 #15 · Is This a Spot on Sensor, or A Sun Spot on Sensor
EB-1 wrote:
You did check the rear of the lens and perhaps try a different lens? Some rear elements are quite close to the sensor.
EBH
That is a good point. I remember years ago having a spot like this and trying to clean the sensor… only to discover that there was something on the rear element.
I’m in the same came as those who wonder about the need for pixel shifting and, based on the other patterns on the image, whether the contrast and luminosity have been cranked way, way up to make a “spot” visible that would not be visible in a normal photograph.
Question to OP: Let’s say you aim the camera at open sky at f/16 and make a normal exposure. Do you see the spot?
Finally, one more thought. I have to improvise the explanation a bit since I’m away from my gear, but IIRC some of the spot removal tool vendors sell two different versions of the liquid used to clean sensors, one water based and the there solvent based. If something is stubbornly stuck to the sensor, it may be that the latter would be more effective.
p.1 #17 · Is This a Spot on Sensor, or A Sun Spot on Sensor
Different lens and two apertures. Size changes with aperture and spot location different than with other lens. So, this isn’t the sensor. I guess the question now is is it the rear elements of these lenses, or the cover glass.
Next set, different lens and looks totally different, so am I correct in thinking that I’ve simply been imaging rear lens glass debris?
Loxia 85mm @f/22focused at infinity and single shot mode:
p.1 #18 · Is This a Spot on Sensor, or A Sun Spot on Sensor
bwcolor wrote:
Different lens and two apertures. Size changes with aperture and spot location different than with other lens. So, this isn’t the sensor. I guess the question now is is it the rear elements of these lenses, or the cover glass.
Loxia 85mm @f/22focused at infinity and single shot mode:
I think when you were wiping the sensor, you were wiping the cover glass/microlens. It is considered part of sensor for practical purpose. Location won't change in that case. I think it's the lens.
p.1 #19 · Is This a Spot on Sensor, or A Sun Spot on Sensor
Thanks to everyone that helped me to understand the process that is used to isolate the source of such a problem. It started with me noticing smudges when copying negatives and thinking there was an issue with the lab. Luckily, I quickly realized that the same smudges extended beyond one negative and some were in the same location.
I have now carefully cleaned the rear elements of the offending lenses and all spots are gone. So, again, thanks for taking your time to respond to this thread.
p.1 #20 · Is This a Spot on Sensor, or A Sun Spot on Sensor
bwcolor wrote:
Thanks to everyone that helped me to understand the process that is used to isolate the source of such a problem. It started with me noticing smudges when copying negatives and thinking there was an issue with the lab. Luckily, I quickly realized that the same smudges extended beyond one negative and some were in the same location.
I have now carefully cleaned the rear elements of the offending lenses and all spots are gone. So, again, thanks for taking your time to respond to this thread.
The reason I thought of it is that once in the rainforest when using the RF 600/4 and 1.4x, condensation formed on the teleconverter and made a circular mark on it after drying. With DSLRs the rear elements are far from the sensor but many are very close in the MILS. Now we should all be careful to clean the rear elements since dust or spots can more likely affect the image.
