Problem with Sony A7, reflections on the sensor.

Started Jan 26, 2014 | Discussions
ncsakany
ncsakany Senior Member • Posts: 1,840
You're right; I stand corrected
1

Here's one at f/13 shooting into the sun. Clearly there are some reflections visible. However, since I didn't buy the camera to 1) shoot at f/13 and 2) into the sun and 3) analyze reflections, to me, personally, this is a non-issue.

At f/22 it's even worse:

birket Contributing Member • Posts: 977
Re: You're right; I stand corrected
1

I used to get these sort of red grid-like patterns with bright light sources on my Sigma DP1 and SD15 cameras. The DP1m improved things a bit.

...found this link showing the issues I had http://rftobler.at/Photography/Tests/Sigma-DPxM-Flare/

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PRESENZA76
OP PRESENZA76 New Member • Posts: 12
Re: You're right; I stand corrected

I wrote to Sony, do you also, we feel our disappointment, hoping that solves the problem.

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stevo23 Forum Pro • Posts: 15,246
Re: You're right; I stand corrected
1

ncsakany wrote:

Here's one at f/13 shooting into the sun. Clearly there are some reflections visible. However, since I didn't buy the camera to 1) shoot at f/13 and 2) into the sun and 3) analyze reflections, to me, personally, this is a non-issue.

At f/22 it's even worse:

It occurs to me that one can obtain sunstars and minimize this with just the right aperture. Up above, at f13, I find it acceptable even when enlarged. Ultimately, those spots look pretty cool if you ask me.

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Jefenator
Jefenator Senior Member • Posts: 2,402
Re: You're right; I stand corrected
1

Sun stars can be a messy business, regardless - especially when I get those big gaudy green teardrop-shaped lens-induced ghosts in the frame (ugh…)

I do believe that the reflection thing is an issue with the A7. Not as pertinent as the obsolete / MF / pricing / compatibility issues I have with most other systems but an issue nonetheless. Folks who plan to do a lot of wide angle night shots with Christmas lights or street lamps (or similar) near the edge should probably steer clear.

As for me, it's nowhere close to being a deal-killer. And sun stars are actually a big deal for me - usually more centrally located. (Somehow, my A7 actually gives me less ghosting problems w/ 50-60mm macro lenses than the NEX-7 used to.)

Pretty Clean Sun Star w/ A7

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PRESENZA76
OP PRESENZA76 New Member • Posts: 12
Re: You're right; I stand corrected

A7 with Leica M Summicron 90 APO ASPH @ F11

LEICA M TYPE 240 with Leica M Summicron 90 APO ASPH @ F11

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becomeAchildAgain Junior Member • Posts: 30
Re: Problem with Sony A7, reflections on the sensor.
1

is this not the same issue pointed out by photographylife.com here:
http://photographylife.com/red-dot-flare-issue

they claim it affects mirrorless systems primarily due to the flange distance..

cheers..

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Jefenator
Jefenator Senior Member • Posts: 2,402
Re: You're right; I stand corrected

PRESENZA76 wrote:

A7 with Leica M Summicron 90 APO ASPH @ F11

LEICA M TYPE 240 with Leica M Summicron 90 APO ASPH @ F11

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If you have the means, more power to ya!

So it looks like the issue with the A7 also happens at telephoto lengths, and the worst situation is point sources at night. (The reflection of my snoot light on the illuminated subject not being quite drastic enough to cause a problem.)

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ProfHankD
ProfHankD Veteran Member • Posts: 5,274
Re: Problem with Sony A7, reflections on the sensor.

becomeAchildAgain wrote:

http://photographylife.com/red-dot-flare-issue

they claim it affects mirrorless systems primarily due to the flange distance..

I doubt that is correct. There are all sorts of sensor reflection issues possible, but the difference between mirrorless flange distance and DSLR flange distance is irrelevant when optically identical lenses are used on both, because the lens distance to the sensor is the same for the same focus distance.

Reflections off the sensor, shiny things between the lens and sensor (e.g, pins in the adapter), and internal to the lens reflections all play a role, but usually complex flare patterns have lens-internal sources. Typically, this will happen because the lens has a complex formula with many elements and thus many surfaces to reflect internally.

Oddly enough, the colors seen can be somewhat camera dependent because even lens-internal reflections may be in various parts of the spectrum, and sensitivity outside the usual R-G-B range varies widely with different sensors -- CMOS sensors generally have a lot of NIR sensitivity, and recent Sony sensors certainly seem to. Different camera models using the same sensor also can vary, because the "sensor stack" (filters on top of the sensor) may be quite different.

In summary, there are many sources of, and differing sensitivities to, flare. It's good to be aware of tendencies to create flare patterns, because that will alert you to examine the shot carefully when you're still on scene and could reshoot, but I think that is still the state-of-the-art answer as to how to get rid of flare -- recompose and reshoot.  

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martindesu
martindesu Senior Member • Posts: 1,245
Re: Problem with Sony A7, reflections on the sensor.

But some reports suggest this isn't an issue with the A7R...

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ProfHankD
ProfHankD Veteran Member • Posts: 5,274
Could it be related to PDAF sensel pattern?

martindesu wrote:

But some reports suggest this isn't an issue with the A7R...

Well, there is a chance that it has to do with either the spectral properties or some aspect of the sensor stack. I suppose the most likely part of the stack would be the microlenses. If so, it would involve a very specific interaction between that particular lens and the microlenses. I suppose there is a possibility that it has to do with the pattern of PDAF sensels...?

I have an A7 and have not seen this effect on any of my lenses so far... although I haven't played with all 130+ lenses I have on the A7 yet. The only other body I have with PDAF on the main sensor is a Canon EOS-M, and I haven't seen this effect on it either.

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seachicken2000
seachicken2000 Veteran Member • Posts: 3,214
Re: Could it be related to PDAF sensel pattern?
1

ProfHankD wrote:

martindesu wrote:

But some reports suggest this isn't an issue with the A7R...

Well, there is a chance that it has to do with either the spectral properties or some aspect of the sensor stack. I suppose the most likely part of the stack would be the microlenses. If so, it would involve a very specific interaction between that particular lens and the microlenses. I suppose there is a possibility that it has to do with the pattern of PDAF sensels...?

There's a post earlier in this thread (and another on Ken Rockwell's site) showing this flare pattern with the A7, and not with a Leica, for images shot in close to identical conditions. This seems to point the finger at the sensor.

Sensor-related explanations I've come across:

  • The sensor itself acts as a diffraction grating causing the dot patterns
  • The patterns are caused by reflections of the sensor on the sensor toppings
  • The patterns are caused by reflections of the sensor on the rear element of the lens

The array of dots in the flare, does look rather like an interference pattern.

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geo444
geo444 Regular Member • Posts: 483
Reflections are mainly outside the PDAF Area !...

ProfHankD wrote:

I suppose there is a possibility that it has to do with the pattern of PDAF sensels...?

.

Reflections are mainly outside the PDAF Area :

http://www.dpreview.com/forums/post/52986307

http://www.dpreview.com/forums/post/52986357

http://www.dpreview.com/forums/post/52986644

http://www.dpreview.com/forums/post/52986667

http://www.dpreview.com/forums/post/52986338

http://www.dpreview.com/forums/post/52988150

from DPReview : PDAF Area (red crosses) in the center of frame

from DPReview : PDAF Area = 13x9 AF points in the center of frame

MISTERX Regular Member • Posts: 172
Re: Reflections are mainly outside the PDAF Area !...

I noted one issue and was thinking the lens was causing the problem not the sensor.
In my case was the voightlander 15mm that shown the UFO´s that can be seen in the attached picture.   I made a series of pictures using different f-stop positions and get different amount of UFO´s

these reflections go in the opposite way as the other shown here.

As the lens is a lens designed for mirrorles, no retrofocus, and with a curved rear element  perhaps the position of the reflections go outer to the frame as the ones taken pointing to the sun directly.

It looks the the problem in this post is the same as mine but a different situation.

I see the f-stop position change the number of rflections and perhaps pointing to the sun interact with the anti- aliasing filter and makes a different moire.

At this point I wonder if we are dealing with a issue as the famous fuji sensor the X10 had.

cxsparc
cxsparc Veteran Member • Posts: 3,424
Re: Reflections are mainly outside the PDAF Area !...
1

Well, look at this:

Strangely, this is NOT the A7 or A7r, but the lowly Nex 5N with a SLR-lens FDn24 at some ridiculous f-stop, maybe f16 or something.

Point being, that this kind of reflections are not a new issue, only the intensity of the A7 may be tougher.

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ProfHankD
ProfHankD Veteran Member • Posts: 5,274
Re: Reflections are mainly outside the PDAF Area !...

MISTERX wrote:

At this point I wonder if we are dealing with a issue as the famous fuji sensor the X10 had.

Definitely not!  Here's my technical publication on the Fuji X10 white orbs and a little free software tool I wrote to fix them, DeOrbIt.

Basically, I see no signs of sensor bloom nor botched color interpolation in the A7 images.

The catch is, I have an A7 and have yet to see this artifact in my shots....  I've been actively trying to get it for a day now so that I can give it full analysis.  

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stevo23 Forum Pro • Posts: 15,246
Re: Reflections are mainly outside the PDAF Area !...

MISTERX wrote:

I noted one issue and was thinking the lens was causing the problem not the sensor.
In my case was the voightlander 15mm that shown the UFO´s that can be seen in the attached picture. I made a series of pictures using different f-stop positions and get different amount of UFO´s

these reflections go in the opposite way as the other shown here.

As the lens is a lens designed for mirrorles, no retrofocus, and with a curved rear element perhaps the position of the reflections go outer to the frame as the ones taken pointing to the sun directly.

It looks the the problem in this post is the same as mine but a different situation.

I see the f-stop position change the number of rflections and perhaps pointing to the sun interact with the anti- aliasing filter and makes a different moire.

At this point I wonder if we are dealing with a issue as the famous fuji sensor the X10 had.

Very cool scene by the way!

Yours doesn't look like the same issue to me. Someone needs to fully characterize this phenomenon.

It looks more lens oriented. Here's from the Korean 24-70 review at slrclub.com:

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Chad Hardy
Chad Hardy Senior Member • Posts: 1,192
Re: Reflections are mainly outside the PDAF Area !...

Hehe you may need grab that solar filter off of your telescope and put it on your sun glasses, then hold the a7 up to the direct sunlight and take a few shots!

I have the a7 with FE 35mm 2.8, no noticeable issues thus far.  However I haven't specifically tried to recreate this.  I will give it a shot when I get back in town Friday.

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Ayan Dakshi Contributing Member • Posts: 677
Re: Problem with Sony A7, reflections on the sensor.
2

Hello everyone, This phenomenon is real and observable in A7R too. Recently I rented A7r and native 35mm 2.8 Zeiss lens. Here is the sample

A7R with 35mm 2.8 @ f14

This completely ruined my photo. I believe you can see this reflections at f11.

Here is another shot with almost similar setting with A900 and Minolta 17-35 2.8-f4

A900 with Minolta 17-35 f2.8-4 @ f13

There are no sensor reflections here.

So, if you want sunstars, A7 and A7r are useless. I am really annoyed and it is a glaring QC issue. Didn't Sony test @ f13 with the 35mm lens. I can't believe it.

A7R is a landscape camera and you cannot shoot at f13 with wide lenses and with sun in the frame! Unbelievable.

Ayan

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slpianoproject Forum Member • Posts: 83
Re: Problem with Sony A7, reflections on the sensor.

Noob question here but would the LA-EA4 with his mirror help in any way about this problem? Increasing the distance between lens and sensor + the mirror?

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