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Sun YS 70-210 zoom
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PostPosted: Sun Feb 07, 2010 3:01 am    Post subject: Sun YS 70-210 zoom Reply with quote

Hi Can anyone tell me why there are dark edges on these photos is it because of the hood or something worse?Just a note for all you suffering from the cold this was a 40 degree day and I was worried about the lens sweating!!

@70


@210


Closer (we moved closer that is Smile )

Closest


Same lens but different View with vegetation...note the bottom right corner is this an error with the lens? I was resting it on a bridge rail.


PostPosted: Sun Feb 07, 2010 3:29 am    Post subject: Reply with quote

It seems to be the shade (not lens vigneting), but did you try any pic without the shade?.

If you haven't film in the cam, put at the film place a piece of ground glass, and with the lens focus to the sky. Not use the shade. Any vignetting? Not the lens shade. To confirm you can use the shade and see if vignetting. That's easy and will be enought.

Good luck. Rino.


PostPosted: Sun Feb 07, 2010 3:36 am    Post subject: Reply with quote

I used the hood on all shots as it was a very sunny day.What would ground glass be?I have a front element from a broken lens I can use? or do you mean a neutral piece of glass.. such as a flat piece?
Thanks for the tip.


PostPosted: Sun Feb 07, 2010 4:20 am    Post subject: Reply with quote

Ground glass: http://www.dokasphotos.com/techniques/ground_glass/


PostPosted: Sun Feb 07, 2010 4:44 am    Post subject: Reply with quote

Thanks I would have had no idea otherwise Smile ...does the thickness need to be precise?


PostPosted: Sun Feb 07, 2010 5:29 am    Post subject: Reply with quote

Nice shots, 4 and 5 work very well. Maybe PP a bit more contrast in 5

Groundglass thickness doesn't matter if the ground (matte) surface is flush against the film plane, where the film would be.

Alternately wax paper or Scotch tape can work too, if you can stick them down tight.

Rino is correct, you should be able to tell just by checking with and without the hood. The film plane check with groundglass, etc. would be extra.

What aperture did you use for these ?

My guess is the lens (hood or not) may indeed be vignetting at larger apertures. The circle of coverage is smallest at large apertures and focus at infinity - your samples are all at infinity pretty much. See if you get the same effects if you stop down to f/16.


PostPosted: Sun Feb 07, 2010 6:44 am    Post subject: Reply with quote

The river shot is F16 speed 250
Here is a link to my other thread about the YS the cat shot would have been closer but unsure of the F stop
http://forum.mflenses.com/sun-zoom-70-210-what-mount-t22448.html

I don't have any PP software other than what comes with windows live gallery or anything in Gimp which I am playing with.Unsure on a lot to do with the "how to" of PP'ing a photo....for the moment I am focusing on getting the exposure right. Very Happy and using different films ie iso 100 compared to 200/400 and then a little B&W and down the track maybe some slide film, until I can get a DSLR to try these lenses out on.