A newbie question - (Part III)

[raytoei@gmail.com]

hi,

To recap: I experienced white patch in some of my outdoor photos with a FED-2 and Industar-26m.

see:
http://www.retro.ms11.net/fed2-c.jpg
http://www.retro.ms11.net/fed2-a.jpg

Some suggested weak curtains or light leaks, while other suggested flare of the lens, or even lens defect. When I checked my curtains using a torch light in pitched darkness, I could not find any white spots indicating holes.

Today, I did several tests using different positions and different lens, all in a 30mins period at Noon.

Shot Left, Middle, Right angle all at infinity focus and at the Table at close range. Repeated the tests for Industar-50 collapsible, a different Industar-26m, and a Industar-61 L/D.

I then proceeded to test Indoor shots with the same three lens but at distances 1m, 1.5m, 2m and 2.5m

The noon shots were mainly 1/500s at F/11 or F/16 while the indoor shots were 1/30s and f/2.8 except for the industar-50 which max aperture is f/3.5.

Here are the abridged versions where I cramped 3 photos for each lens in each outdoor and indoor scenario:

http://retro.ms11.net/i-50-outdoors.jpg
http://retro.ms11.net/i-50-indoors.jpg

http://retro.ms11.net/i-26m-outdoors.jpg
http://retro.ms11.net/i-26m-indoors.jpg

http://retro.ms11.net/i-61-outdoors.jpg
http://retro.ms11.net/i-61-indoors.jpg

Observations and Questions:
----------------------------------------
a. My new shiny Industar-50 is a problem kid. I am not sure if it is faulty or I did not extend the collapsible lens fully resulting in poor focus. (Can someone comment on this ?)

b. The Industar-26m seemed to flare in the outdoor photo, the first photo looked overexposed and the Sun was overhead on my left. (Or this could be a light leak due to lens change ?)

c. The Industar-61 L/D performed the best, the first photo was accidentally overexposed, ( I changed lens and forgot to set the aperture). (The first photo and 3rd photo are the same angle with the Sun overhead on my left).

Indoors, my 3 lens performed similarly to the outdoors with the I-61 being the sharpest.

Conclusion: I did not experienced the White Spot ever since I stopped using the previous I-26m lens. Perhaps this is a lens defect in the old I-26m. I shot during Noon at 3 angles and it did not experience flare except in the first photo with the new I-26m lens which showed a flare but did not occur again in the subsequent photos. I also need to do more tests for my I-50.

thanks!

raytoei

 

[julio1fer]

The Industar-50 collapsible is a very sharp lens. It has to be extended fully out, and then rotated to lock. If not, you'll get unsharp results (don't ask how I know).

Are you using a tripod for these tests, and measuring with tape to set focus?

 

[raytoei@gmail.com]

Julio1er,

Yes to Tripod, Measuring Tape and Shuttle release cable. The tripod mount isn't very good because I add the attachment for the old mounts and it is sort of loose 🙂

thanks for the tip on the I-50.

 

[raytoei@gmail.com]

julio 1 fer,

Thanks. I tested the I-50 on my FED-3 yesterday and it works perfectly!

raytoei

 

[martinsmith99]

I have found the same on my I-26. It was used on a bright sunny day. I even have the lens hood attached, but it seems the slightest bit of stray light and it flares. My J-11 & J-8 do not suffer the same problem.

Incidentally, I've just got the Industar 61 for my M42 SLRs. Fantastic lens!

 

[Valkir1987]

Dear Raytoei,

Check the surface of the I-26 for scratches with another lens or magnifier. I had the same haze/flare with an I-22 that had scratches on the front element.
Check for dust and oil on the aperture blades that can reflect light.

A hood and 'uv or skylight' filter may help as well.

Keep up with your Fed 😉 Succes!