Flare Problem With Tamron SP 90mm f2.5

Harold Gough · Post by **Harold Gough** » Wed Nov 16, 2011 11:29 am

This may be of interest to users or potential users:

http://forum.manualfocus.org//viewtopic.php?id=16344

Harold

Harold Gough · Post by **Harold Gough** » Fri Nov 18, 2011 3:15 am

Here is an image taken at f8. There is an indistinct purple blob on the largest bunch of berries.

Harold

ChrisR · Post by **ChrisR** » Fri Nov 18, 2011 6:23 am

I've seen this before and wondered about users who have filters in the optical path, which introduce a reflective surface parallel with the sensor.
Anyone see problems?

ChrisLilley · Post by **ChrisLilley** » Fri Nov 18, 2011 10:00 am

I used to use high quality B&W uv filters 'for protection'. I now use metal lens hoods instead, for this reason. You never know when one of these artifacts is going to show up.

I notice that the forum posting in the original post was not using a hood.

Harold Gough · Post by **Harold Gough** » Fri Nov 18, 2011 10:10 am

I did a 'quick and dirty' test today. Im took thre successive images of some foloaige backlit bt the sun, a worst case. This time the foloage forms the centre of the imge, showing the flare more clearly.

The first image is with a lens hood but no filter. The second is with neither. the third is with hod and Hoya HMC skylight filter. The lens was at f8 and the distance to the subject something like 10 feet/3m.

I haven't got the exposures exactly the same but you can see that the effect is much the same.

With a converter there is no flare.

Harold

naturephoto1 · Post by **naturephoto1** » Fri Nov 18, 2011 10:23 am

Hi Harold,

In most instances you should be able to see the lens flare issue in the camera viewfinder before you take the photograph. You may wish to consider repositioning yourself when this happens to remove the issue; this will of course have some affect on the composition. Lens flare like this is frequently more noticeable when the camera lens is facing directly into the sun or the sun is actually partially in the photo frame. Also as others have indicated, whenever possible try to use a lens hood. Multicoated filters may help, but a filter on the front of a lens (no matter how good) can at times present an additional reflective surface that can cause lens flare. I watch for this, though I normally use very high quality UV filters on the front of my lenses whenever possible and use a lens hood or shade the lens if not possible or practical when the camera is mounted onto a tripod.

Rich

Harold Gough · Post by **Harold Gough** » Fri Nov 18, 2011 10:42 am

naturephoto1 wrote:
In most instances you should be able to see the lens flare issue in the camera viewfinder before you take the photograph. You may wish to consider repositioning yourself when this happens to remove the issue; this will of course have some affect on the composition. Lens flare like this is frequently more noticeable when the camera lens is facing directly into the sun or the sun is actually partially in the photo frame.

I deliberately set up a worst case for my favourite aperture, having not seen it in my images.

Yes, I can see the flare in the viewfinder.

Yes, pointing it away from the light source by even a small amount loses the flare very quickly.

Should I wish to shoot an image close to a strong light source I now know that a TC prevents such flare.

Harold

rjlittlefield · Post by **rjlittlefield** » Fri Nov 18, 2011 10:43 am

naturephoto1 wrote:In most instances you should be able to see the lens flare issue in the camera viewfinder before you take the photograph.

That's normally good advice, but it may not apply in this case. The problem described at http://forum.manualfocus.org//viewtopic.php?id=16344 and illustrated here seems to be caused by light bounding back and forth between the sensor and the flat rear element of the lens. It should be visible in Live View, because then the display is showing very close to what will eventually be recorded. But it may not be visible when viewing through an optical viewfinder, because then half of the cause is gone. No flat and reflective sensor, no glare spot.

--Rik

rjlittlefield · Post by **rjlittlefield** » Fri Nov 18, 2011 10:49 am

Harold Gough wrote:Yes, I can see the flare in the viewfinder.

Harold, can you clarify: is this through an optical viewfinder, or on the electronic viewfinder of your E-P2?

--Rik

naturephoto1 · Post by **naturephoto1** » Fri Nov 18, 2011 10:52 am

rjlittlefield wrote:
naturephoto1 wrote:In most instances you should be able to see the lens flare issue in the camera viewfinder before you take the photograph.
That's normally good advice, but it may not apply in this case. The problem described at http://forum.manualfocus.org//viewtopic.php?id=16344 and illustrated here seems to be caused by light bounding back and forth between the sensor and the flat rear element of the lens. It should be visible in Live View, because then the display is showing very close to what will eventually be recorded. But it may not be visible when viewing through an optical viewfinder, because then half of the cause is gone. No flat and reflective sensor, no glare spot.

--Rik

I am more familiar with the issues working for so many years with my film based cameras in 35mm up to 4" X5". As you point out the the live view that is my situation for my Panasonic Lumix G1 (electronic viewfinder) so I would expect to quite likely see it if it should arise with this camera. I suspect though that with something like my Canon G9 or G10 since these neither have the live view nor through the lens viewing that this could well be an issue. The same would quite possibly be an issue with my Mamyia 7II.

Rich