View single post by Robert
 Posted: Fri Mar 22nd, 2019 04:42
Robert



Joined: Sun Apr 1st, 2012
Location: South Lakeland, UK
Posts: 4066
Status: 
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It was July, 2009.  That was before this forum had it's last change of software, so unfortunately the thread is gone forever.  However, I have found the images and even better, they are notated with the makes and details of the filters I tried in the experiment I carried out.

I was using a D1x with  my Nikkor 50mm f1.4 lens at the time. It all  started because I wanted to take a side-lit photo of my son, Christopher.  I was experimenting with the lighting and positioning the camera and subject to get the best effect. I didn't realise at first but the contrast was being seriously reduced.  Then the penny dropped, the lighting was causing the problem but why?

I tried several 52mm UV filters and the effect varied somewhat so I went the whole hog and removed the UV filter entirely.  Viola! Contrast restored, then I realised there was ghosting which at first I hadn't understood.

This was the first image, the UV filer was not marked with a manufacturers name. Christopher wasn't a good sitter!
#1


This was the second image, the UV filer was not marked with a manufacturers name.
#2


This is the third image, this filter was marked 'Helios UV'.
#3


This is the fourth image, this filter was marked 'Nikkor L39'.
#4


This is the fifth image, the filter was marked 'Hoya Skylight'
#5


Finally, the sixth image, with NO FILTER.
#6


This is the picture I wanted, taken some time after the above series of test exposures, once I had satisfied myself that the UV filter was to blame.



I took many other exposures at the time hence the various degrees of boredom on Christopher's face as I tried the different filters and various positions to try to minimise the glare and ghosting.  Those tests convinced me that the perceived benefits of using UV filters were far outweighed by the real and serious image degradation I experienced.  I also recognise similar effects in images which I couldn't understand why they were lack-lustre, I now put that down to using a UV filter.

The 'better' filters didn't perform better than the unbranded filters, in fact image #1 with an unbranded filter could be considered among the least affected.

I would be very interested is someone else fancied doing a similar test series...  Since then I dumped all my UV filters except the one which seems to be glued to my Nikkor 80-200 f/2.8 trombone lens.  I would dearly like to remove that but fear the forces needed to remove it would do damage to the lens, so I have to weigh that against the effects it has on my images.



____________________
Robert.