Is the dreaded digital "red spot" gone?

[Michael Bailey]

When I used my dear departed Fuji S-2 to photograph subjects on white backgrounds, I'd wind up with soft translucent red areas in the center of the finished photos. I figure the spots were generated by light bouncing off the face of the sensor, onto the back of the lens, and then back into the photo receptors. (I've never read another explanation for this behavior, so if anybody knows better, I'd be interested to hear from you.) The problem was bad enough that I had to sell a couple of lenses for which the problem was especially bad. (Nikon 50mm,f.1.4, Tamron 90mm,f.2.5)

Now I'm using a Nikon D-700 and thinking about finding another Tamron 90mm. Does anyone know whether the red-spot problem has been licked, at least with my current camera? Or should I continue to steer clear?

Thanks,               MB

[DarkPenguin]

If the lens is marked as being for digital (and I think the 90 has been updated) it should have anti reflective coatings on the rear elements.  This should (largely) eliminate the issue.

[Dustbak]

There were more than several lenses that exhibited this phenomena. I have seen it with my Nikkor 85PC, Zeiss ZF50/2.0 macro. My spot was blueish or greenish. I have never seen it with DSLR's but did see it while using the Digiflex II and several different backs.

It is good to finally see someone else that has noticed the same thing  When I reported this issue to Zeiss they initially thought I was nuts but eventually had to admit this was an issue with their lens that could not be resolved.

[Jonathan Ratzlaff]

I saw the same thing with my s-2 and the tamron 90 2.5 and the nikkor 50 mm1.8.  However I haven't seen this with the D90.  

[Michael Bailey]

Original Poster here. Thank you all for your replies. Jonathan, I appreciate that you've had experience with one of the exact models of lens I was talking about. It makes me more optimistic as I consider a new portrait lens. (I've been using a Micro AF 105,f.2.8, which is good for tabletop, but somehow I can't quite get used to it for portraits. Maybe I'll even think again about the 105/2.5 Nikkor that I loved using for so many years!)
Thanks again,                          MB

[brianc1959]

When I used my dear departed Fuji S-2 to photograph subjects on white backgrounds, I'd wind up with soft translucent red areas in the center of the finished photos. I figure the spots were generated by light bouncing off the face of the sensor, onto the back of the lens, and then back into the photo receptors. (I've never read another explanation for this behavior, so if anybody knows better, I'd be interested to hear from you.) The problem was bad enough that I had to sell a couple of lenses for which the problem was especially bad. (Nikon 50mm,f.1.4, Tamron 90mm,f.2.5)

Now I'm using a Nikon D-700 and thinking about finding another Tamron 90mm. Does anyone know whether the red-spot problem has been licked, at least with my current camera? Or should I continue to steer clear?

Thanks,               MB

If the spot gets more pronounced as you stop down, then it is a ghost image of the aperture stop.  In some lenses the ghost image is so well defined that you can actually count the iris blades.  It can be caused by a sensor reflection followed by a lens surface reflection, but it can also be caused by a pair of lens reflections.

[Michael Bailey]

Original poster here, many months later.

I've had a chance to try that Tamron Adaptall 90mm again. Turned out I hadn't sold it but instead loaned it to a friend and forgotten that he had it until I noticed it on his shelf. So, while setting up for a portrait, I shot a couple of tests of myself against an illuminated white background. (It read about 250-250-250 in Photoshop when the exposure on my face looked right.) I looked at the resulting files, carefully removed the lens from the camera, gently placed it as far back in the cabinet as I could, and walked silently back to the camera, stopping only long enough to pick up a Nikkor 85mm 1.8.

In short, that red spot was bad, bad, bad. The change in camera did not improve the situation at all.

[JohnBrew]

This was news to me so I very carefully went over all my Zeiss 50 Makro shots with the D-700. I can't find anything resembling what you have mentioned - even under harsh lighting. This could be sample variance, I suppose.

[Michael Bailey]

Hi John,

I suspect that your Zeiss macro is a post-digital design and would therefore be alright as far as this particular problem is concerned. Keep in mind, too, that the spot shows up when there's a bright background, so you might not notice it until it sneaks up on you!   MB

[tbosley]

Now I'm using a Nikon D-700 and thinking about finding another Tamron 90mm. Does anyone know whether the red-spot problem has been licked, at least with my current camera? Or should I continue to steer clear?

Thanks,               MB

Do not know about Tamron lenses, but this issue was given tons of attention back with the Kodak 14n.  So much so that Kodak made a FAQ on the problem.

[Ken Bennett]

In short, that red spot was bad, bad, bad. The change in camera did not improve the situation at all.

Well, yeah, one main cause of this issue is light reflecting from the sensor back into the lens. Modern digital lenses have anti-reflection coatings on the rear elements, which helps prevent this. Using the same lens I wouldn't have expected different results.

[Michael Bailey]

Using the same lens I wouldn't have expected different results.

I guess I was hoping for improvements in sensor coatings. (Do they even have coatings? Beats me!)

 MB

[NashvilleMike]

I guess I was hoping for improvements in sensor coatings. (Do they even have coatings? Beats me!)

 MB

It's a lens design problem and lenses that have been designed since the advent of the DSLR usually don't have the problem. Sensors have coatings, but by the nature of them they are going to be more reflective than film. The problem actually existed in the "film" era, but film wasn't as reflective so the results were far more subtle.

The two most well known "hot spot" problem lenses in the Nikon lineup were and still are the 50/1.8 and 85/1.8 lenses - both of those are on my "avoid" list no matter how popular they might be with the affordable lens crowd over in some other digital forums. I've had images ruined with both of those lenses because of that problem and didn't know what was going on until Nikon writer Thom Hogan mentioned it in one of his newsletters he used to publish several years ago - I think I first heard about this in '04 give or take.

The Zeiss lenses, at least initially, were designed more with film in mind, but honestly I've never heard of anyone having hot spot problems with them on any body, but I don't own any of them so can't say for myself.

-m

[Michael Bailey]

...The two most well known "hot spot" problem lenses in the Nikon lineup were and still are the 50/1.8 and 85/1.8 lenses - both of those are on my "avoid" list no matter how popular they might be with the affordable lens crowd over in some other digital forums.

Hi Nashville Mike,

First, if you are really in Nashville right now, I am sorry to read about the flooding you all have been experiencing. I hope you and yours have made it through without problems. If you're just a dedicated fan of country music and live somewhere else, well, the sympathy for Nashville still applies.

So, back to the lenses. It's interesting that you mention the 85mm 1.8 as an offender, because that's the lens that I've been using in place of the old Tamron 90. I haven't had any problem with it, even though I used it on the same set right after I put down the 90. Mine is an AF-D version. Maybe the problem was with the manual focus model?
MB

[NashvilleMike]

Hi Nashville Mike,

First, if you are really in Nashville right now, I am sorry to read about the flooding you all have been experiencing. I hope you and yours have made it through without problems. If you're just a dedicated fan of country music and live somewhere else, well, the sympathy for Nashville still applies.

So, back to the lenses. It's interesting that you mention the 85mm 1.8 as an offender, because that's the lens that I've been using in place of the old Tamron 90. I haven't had any problem with it, even though I used it on the same set right after I put down the 90. Mine is an AF-D version. Maybe the problem was with the manual focus model?
MB

Got lucky here - no flood issues where I'm at. Not a fan of country music nor southern cooking as I'm a transplanted Yankee living here   Thanks for the thoughts though, some areas of town are still in rough shape.

As for the 85/1.8 - yup, the 85/1.8 AF-D is a known culprit. It's somewhat easy to avoid - don't shoot at or particularly beyond F/11 in any scenario where there's a lot of light reflecting back at you. I've had shots from White Sands NM (in the dunes) with the lens at F/11 ruined as well as some studio shots of a model with a black dress shot against a white background. Needless to say, after that, I no longer own the lens; it's been replaced with the 85/1.4 AFD (and 70-200/2.8 VR2), both of which don't exhibit the problem.

-m

[Michael Bailey]

Got lucky here - no flood issues where I'm at. Not a fan of country music nor southern cooking as I'm a transplanted Yankee living here   Thanks for the thoughts though, some areas of town are still in rough shape.

As for the 85/1.8 - yup, the 85/1.8 AF-D is a known culprit. It's somewhat easy to avoid - don't shoot at or particularly beyond F/11 in any scenario where there's a lot of light reflecting back at you. I've had shots from White Sands NM (in the dunes) with the lens at F/11 ruined as well as some studio shots of a model with a black dress shot against a white background. Needless to say, after that, I no longer own the lens; it's been replaced with the 85/1.4 AFD (and 70-200/2.8 VR2), both of which don't exhibit the problem.

-m

Glad to read that you did okay. My tastes run more toward Memphis than Nashville. What a difference 200 mile can make.

So I'm still trying to figure out why this 85 is such a problem for others but has been perfect for me. Could it be that when I use it in studio the background is white but not "blown out" white? I think I mentioned earlier that I usually place backgrounds values at about 250 out of 255. That was enough to wreck pictures from the Tamron, so maybe the Nikon 85 is bad, but just not as bad as the other, and not bad enough to show up in the set-ups I've used so far. I usually shoot around f-11, sometimes closer to 8.
  MB

[NashvilleMike]

Glad to read that you did okay. My tastes run more toward Memphis than Nashville. What a difference 200 mile can make.

So I'm still trying to figure out why this 85 is such a problem for others but has been perfect for me. Could it be that when I use it in studio the background is white but not "blown out" white? I think I mentioned earlier that I usually place backgrounds values at about 250 out of 255. That was enough to wreck pictures from the Tamron, so maybe the Nikon 85 is bad, but just not as bad as the other, and not bad enough to show up in the set-ups I've used so far. I usually shoot around f-11, sometimes closer to 8.
  MB

You have to be at or beyond F/11 to see it, and only when there is a lot of bounce back light hitting you. The traditional method of lighting a white "blown out" backdrop to read 2 and a third stops hotter than your baseline flash exposure will do it, but if you're much lower than that, you might be lucky.

-m

[Michael Bailey]

You have to be at or beyond F/11 to see it, and only when there is a lot of bounce back light hitting you. The traditional method of lighting a white "blown out" backdrop to read 2 and a third stops hotter than your baseline flash exposure will do it, but if you're much lower than that, you might be lucky.

-m

Thanks, Nashville Mike. I'll keep an eye on this.
 MB