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Need help adjusting infinity focus on Vivitar series 1 28-90
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PostPosted: Wed Apr 10, 2019 4:11 am    Post subject: Need help adjusting infinity focus on Vivitar series 1 28-90 Reply with quote
I noticed today that my vivitar 28-90 stops just shy of reaching infinity focus
I dont know it it's the fault of the lens or adapter but its driving me nuts. Does anyone know an easy to follow way that I can adjust it myself? I'm ok with it focusing past infinity, I just need it to get there.


PostPosted: Wed Apr 10, 2019 8:25 am    Post subject: Reply with quote
You can check whether it is the lens or the adapter easily by placing the lens on the appropriate camera for which its mount is designed.
If it focuses to infinity on that camera, then it is probably the adapter.
I would almost be willing to bet that it is the adapter, as I have seen variations in adapter quality - whereas the lenses have been very consistent.
Tom


PostPosted: Wed Apr 10, 2019 9:13 am    Post subject: Reply with quote
Does the lens itself have an interchangeable lens mount? If so, you could check it is seated correctly, just to eliminate that.

Not reaching infinity means something is too long, if I remember.


PostPosted: Wed Apr 10, 2019 9:38 am    Post subject: Reply with quote
Sciolist wrote:
Does the lens itself have an interchangeable lens mount? If so, you could check it is seated correctly, just to eliminate that.

Not reaching infinity means something is too long, if I remember.


Yes that is correct, but I have never seen a Viv S1 28-90 in anything other than a fixed mount
Tom


PostPosted: Wed Apr 10, 2019 1:57 pm    Post subject: Reply with quote
But also check for loose elements, especially if the lens previously did focus to infinity. Does the lens look like it has been tampered with/cleaned?
Zoom lenses like this are hardly ever misadjusted for infinity focus. Can be an issue with some primes eg a sigma superwide Ii I had to readjust recently see here.

I had a bit of trouble with the viv 28-200/28-210mm zooms, on my lumix the focus was well out as described in this thread.

http://forum.mflenses.com/classic-vivitar-superzooms-review-28-210mm-and-28-200mm-t69878.html

I attribute the issues to the M43-PK adapter.


PostPosted: Wed Apr 10, 2019 6:17 pm    Post subject: Reply with quote
marcusBMG wrote:
But also check for loose elements, especially if the lens previously did focus to infinity. Does the lens look like it has been tampered with/cleaned?
Zoom lenses like this are hardly ever misadjusted for infinity focus. Can be an issue with some primes eg a sigma superwide Ii I had to readjust recently see here.

I had a bit of trouble with the viv 28-200/28-210mm zooms, on my lumix the focus was well out as described in this thread.

http://forum.mflenses.com/classic-vivitar-superzooms-review-28-210mm-and-28-200mm-t69878.html

I attribute the issues to the M43-PK adapter.


The lens doesn't appear to have been tampered with. I guess I could try another adapter and see if anything changes. If it doesn't focus to infinity, would it need to be closer or further from the sensor?


PostPosted: Wed Apr 10, 2019 6:42 pm    Post subject: Reply with quote
Closer. Remember extension tubes move lens farther away losing infinity but gaining magnification of closer distance. Your adapter may be too thick...


PostPosted: Wed Apr 10, 2019 10:22 pm    Post subject: Reply with quote
I ran some more tests on a tripod and higher shutter speed to take camera shake out of the equation, and I think perhaps Its just not quite as sharp of a lens on FF as it was on my A6000. Its hard to tell, but there does seem to be a peak sharpness just before you hit the infinity marker then it gets slightly softer, so it does seem to be reaching infinity, its just a little softer than I was hoping for. But I think I'm also being too much of a pixel peeper and judging it a little too closely. I'll have to take it out and do some real photos, not just judging it off a random test shot.


PostPosted: Wed Apr 10, 2019 10:25 pm    Post subject: Reply with quote
Kawana87 wrote:
I ran some more tests on a tripod and higher shutter speed to take camera shake out of the equation, and I think perhaps Its just not quite as sharp of a lens on FF as it was on my A6000. Its hard to tell, but there does seem to be a peak sharpness just before you hit the infinity marker then it gets slightly softer, so it does seem to be reaching infinity, its just a little softer than I was hoping for. But I think I'm also being too much of a pixel peeper and judging it a little too closely. I'll have to take it out and do some real photos, not just judging it off a random test shot.


Yes, check it out for sure.
My copy is for Nikon mount and it performs much better on the D300 (APSc) than on the D700 (Full frame)
Tom


PostPosted: Thu Apr 11, 2019 8:47 am    Post subject: Reply with quote
What camera?
If you're adapting, I would double check the adapter thickness to make sure it's correct or most likely a tiny bit too thin which would permit focus past infinity.
There are adapters that are too thick which would cause the situation you have.
Rather than opening up the lens to adjust infinity if the adapter isn't too thick, I would rather modify a dedicated adapter to use with this lens since there is less risk to the lens and adapters are relatively cheap.
If this is on a native mount film camera, then yes, you may have to adjust the lens.

Note: I forgot to click post...

I could shoot a few more test shots with my S1 28-90 on my A7r. I don't think it will beat my Leica R 35-70/3.5
A 24MP APS-C should be more demanding than the A7rII & III in the center.


PostPosted: Thu Apr 11, 2019 8:56 am    Post subject: Reply with quote
Lightshow wrote:
What camera?
If you're adapting, I would double check the adapter thickness to make sure it's correct or most likely a tiny bit too thin which would permit focus past infinity.
There are adapters that are too thick which would cause the situation you have.
Rather than opening up the lens to adjust infinity if the adapter isn't too thick, I would rather modify a dedicated adapter to use with this lens since there is less risk to the lens and adapters are relatively cheap.
If this is on a native mount film camera, then yes, you may have to adjust the lens.

Note: I forgot to click post...

I could shot a few test shots with my V S1 28-90 on my A7r.
A 24MP APS-C should be more demanding than the A7rII & III.


The centre performs very nicely on APSc and Full frame.
And on APSc the whole image is crisp
The edges on FX really limp badly on mine
Tom


PostPosted: Thu Apr 11, 2019 7:54 pm    Post subject: Reply with quote
The way to alter the focusing distance on the Vivitar 28-90: locate and undo the three small grub screws at the front end of the lens, which hold the front (focusing) group in place. Once loosened, the front group can be rotated inwards (greater distance) or outwards to taste. Be careful to use a good quality screw driver (flat blade). To rotate the lens group I used one out of a set of ring-removal rubber tools, which contacted on the metal name plate ring to avoid damage to the front element.
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