The 2016 Day Prime Training aka Outtakes thread - Event Date: 01 January 2016 - 31 December 2016

I tried to open my 35-70/3.5 like TheEmrys and other people have done, remove the stops which might make it f2.8-3.5 .

My version is different, in order to completely open the iris I'll have to grind metal because one of the stops is the connecting rod which connects the aperture ring to the blades ... definitely not brave enough for that yet ...

I de-clicked it as well, not sure if that's better for photography, I'm in the habit of knowing exactly what aperture I'm using ....

I wonder if it might be a fraction bigger than f2.8, because I think I'm getting 0.7eV more light now, and it looks like it has another third of a stop left ...

Here is the opening at 35mm and >3.5:

Busy Challenge week coming up. Prepare for lenses.

For Day 52/53/55/57 & 58 (I don't have 60mm prime. Day 60 are Tamron SP 60-300mm)



52mm: Konica Hexanon AR 52mm f 1.8
53mm: UV-Topcor 53mm f 2
55mm: Asahi Pentax Super Takumar 55mm f 2
57mm: Konica Hexanon 57mm f 1.4
58mm: Minolta MC Rokkor-PF 58mm f 1.4

Thank you darosa

I can't find good reasonable 51mm (expensive old lens) or 54mm (projector)lens.
But, I forgot I have a 56mm (Minolta Vectis 28-56).

I use Minolta Vectis S-1 with 28-56mm for doorstop (for real )

There's several Industars "around" 50 mm and max aperture 2.8. Some are engraved 50 mm, but there's also 52, 53 and 55 mm variants. I always wondered if it was just a different number on the lens or if there was a "real" difference in focal lenth.

So yesterday I could do a nice experiment and shot Leo's Industar 24 (52 mm/2.8) vs. my Industar 61 (53 mm/2.8). They both have the LTM thread (M39). Externally they look very much alike, only Leo's copy is shiny bare metal while mine is painted black. But construction and look of the lens is the same, down to the exact same number of grooves in the focusing ring.

So I put my camera on a tripod, and tried to take the exact same shot with both lenses and being very careful not to move the tripod/camera while changing.

The two pictures are below:

Industar 24 (52/2.8)


Industar 61 (53/2.8)


Some conclusions:

• The pictures are not exactly lined up, maybe I still moved the tripod or the optical axis of the lenses are slightly different. Can't be the adapter, since I use the same for both lenses this test.
  
• At full resolution I copied the 53/2.8 picture at 50% opacity on top of the 52/2.8 picture. I then moved the top layer so the left/top corner was exactly lined up. Then looking at the right bottom corner I could see the angle of the 53 mm was indeed a tad smaller then the 52 mm since I had to move the top layer about 30 pixels right and 20 pixels down to exactly line up the details in that corner. So the 1 mm difference in focal length is noticeable.
  
• The contrast and corner sharpness of the Industar 61 (53/2.8) is slightly better then the Industar 24 (52/2.8). Don't know if this is caused by different coatings, different vintage (the 24 "bare metal" is probably older) or just normal sample variation.
  

Anyway, I think this is a pure academic test without much practical implications, but it was fun to do.

Thanks Leo for borrowing your lens and I hope you find these results a proper reward for the generosity of letting me use it   

Day 56 set up.

Minolta Vectis 28-56 with NEX3. (with new adapter set-up)
Can manual focus to infinity to 40cm. Aperture is wide open only.

darosa wrote: That looks professional Hiro. How did you do the adapter?

Thank you! darosa   

Last years Day Prime challenge, I set up with focusing helicoid (M42 to M42) adapter. But I broke it. They use 6 tiny setscrew to hold and I rip the 3 of the screws.

New set up are M42 to NEX Macro Adapter (Unlike regular M42 to NEX (37mm) adapter this one is 1mm thick.

Then unusual Nikon F to M42 adapter and Nikon extension tubes first section. This extension tube inside diameter is almost Vectis lens mount size. Bit tighter. So, I hand filed to made Vectis bayonet shape.

Flange distance is bit shorter. little past Infinity to about 40cm distance. Focus is I grab lens hood then forced turn lens barrel.

I like the matching look of body/lenses plastic texture.


Normal M42-NEX adapter and Macro M42-NEX adapter


All adapters


My Vectis are Nikon mount now. Fit Nikon body and take picture (DX/APS-C, Crop Body) My set-up are Macro only 15-5cm distance.






   

I like it the way it is Richard. If you really feel like cropping perrhaps making the welder less central will add something. Perhaps keeping the darker side and reducing the white top left?