An exceptionally bad Vivitar Kino 28mm f2.5?

[VichySchwa]

Ran some test photos with this lens and want to get some feedback. I had my camera just auto-set the exposure but took 2 pictures of each, one at 5.6 (pictures to me are unacceptably soft/blurred at 2.5), the second at F11 or F16.

Some possible confounding factors:
--I'm still getting acquainted with this Sony A5000 and focusing on a not particularly good LCD screen is challenging in bright light, but I relied on focus peaking. Center of picture should be sharp.

--I had seen what looked like very fine dust or debris when shining light in the lens and opened up the lens. There was the back lens and the the front group of lenses that are housed together. The debris appears to be in the latter part of this lens group. In theory I could open the front lens of the group and get at the inner lenses as I can see there are divots to remove the inner lenses, but the front lens appears to be glued shut.
I carefully put everything back in sequence and nothing felt like it was being tightened out of alignment, but I may have caused some of this.

I don't think just fine debris would cause this almost Helios-like effect. Any different perspectives on this would be appreciated. I can appreciate this effect in general but I would have expected Kino lenses to be more sharp to the edges than this. I have other Vivitars but they are Komine and Tokina varieties, which themselves, while generally middling, are more sharp than this overall.


Tree at f5.6


Tree at f11


Vine at f5.6


Vine at f11


Branch at f5.6


Branch at f16


EDIT:
I decided to go back and take the last shot at f2.5 for you to decide yourself on whether it's too soft/blurred





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[visualopsins]

something loose inside?

[VichySchwa]

[VichySchwa]

Perhaps the adapter might be a factor? no glass inside this as the depth compensates for the flange/focal distance.

[stevemark]

There's certainly something wrong with your lens. I have some samples of the 2.5/25mm and may be able to post an image taken with a 16 MP APS-C camera. I'd guess that either a single lens has been reversed or that a distance between two lens groups isn't as it should ...

S

[alex_d]

if that lens is same as panagor 28/2.5 - then something is wrong with your lens.

if that lens is not the same as panagor 28/2.5 - then something is wrong with your lens.

[lightdreamer]

I too have a 2.5 28mm Vivitar and despite its not a very good lens the performance is far, far better then the pictures you show here. I completely follow stevemarks theory of a damaged repair or assembly.
You need a working example to compare the assembly.

BG

[VichySchwa]

Thanks for the feedback everyone. with the consensus indicating something terribly wrong I suspcted my opening up the lens on the last go may be the culprit. The lens suction cup kit I just received in the mail today came in handy

According to lens-db.com, this is the lens design:


Mine is a later dedicated M42 lens and not the "Pyramid" Kino T-mount, and it has 6 blades instead of 8, but I figured this would be a good enough guide to go off of. The vertical line delineates the front group from the rear group, and the parentheses-shaped lens was flipped 180 degrees and was first in the sequence from left to right. I placed the grouped doublet at the beginning of the sequence and reset the other lens in the correct configuration. just looking through the viewfinder appears to be improved, but I'll take pictures in the same area tomorrow (as long as it doesn't decide to rain all day) to verify my results.

[kiddo]

Interesting character lens for portraits?

[lightdreamer]

[stevemark]

[alex_d]

that lens could work for a portret and a full dark with a flesh


regarding panagor lens version and other legends: my lens is is this one, as new
https://allphotolenses.com/public/files/img/39207f657e85143c3a692c514bb29abb.JPG

i took it out and t reminded my self why im not using t any more; weight and length.

pic quality is good for an vintage lens. so its for sell

[BrianSVP]

That really seems like someone put an element in backwards to me. Generally, I've found this lens to be a surprisingly good performer throughout its various iterations.

Most likely, the offending element is found in the rear cell, as this is where these tend to haze up and require service. Best guess is the rearmost element.

[VichySchwa]

Well at least we're at improved, over the earlier pictures...

Went back to the prominent dead branch, focused on the briar vine just off center, and took the following pictures (ISO and exposure varied as I just had the camera on program):

@ f2.5:


@ f5.6


@ f16


After this I tried a hyperfocal distance exercise. I set the exposure manually to 1/30, lens at f11, and set focus between 5-10 feet according to the f11 lens markings, and tried doing some walk-around pictures around my office, bumping ISO to have the EV at 0. It seems hit and miss and I'm wondering if focus needs to be fixed or if it's just camera shake.

[lightdreamer]

Looks ok now to my eyes. Gratulation

[Slalom]

well done

[Lloydy]

Your recent pic's are ok. I've got three of these lenses, two Kiron - M42 & Minolta mount, and a Tokina with Vivitar's TX mount. None of them are bad lenses at all, but I haven't 'tested' them against the only other 28 / 2.5 lens I have - a Tamron Adaptall 2 02B, which has a very good reputation. And it would be unfair to judge it against the 28 / 2.8's that every big maker made.
The 2.5 lens is about 28% faster than a 2.8 so it's a nice lens to have.

[marcusBMG]

I have the panagor.



These are test pics I took of the castle - pentax K3-ii (24MPX apsc). I have taken same pics with a number of 28mm lenses, I find that most do seem to exibit some field curvature so the end turrets are hard to get sharp, even stopped down a bit. But centre frame this lens is pretty much as sharp as most.

F2.5 click to get full sized..


F8

[kiddo]