Lens Focus Problem - FD Mount Vivitar on GH1

[dmontgom]

Hi everyone,

I just bought a 24mm F2 Vivitar to replace another old prime, my 28mm F2.8 Tamron. I came across the Vivitar on Ebay and it seemed perfect, something slightly wider bringing me to the 50mm ballpark when you account for crop factor. Combine that with the fact it's faster than Tamron and it was well under $200 for an F2... I decided to jump on it.

Unfortunately it's not doing what I expected it to do, and that's actually focus on anything more than a foot away. I know enough about lenses to know about focal lengths, aperture, etc, but not nearly enough to know whether or not this lens is behaving this way due to the adapter (do I need an adapter that's thinner maybe?) or if I bought a faulty lens.

Lens experts, can you please take a glance at this 1 minute video with footage comparing both lenses and let me know what you would do in this situation? Contact the seller, try a diferent adapter, etc. (In other words besides never buying this lens in the first place... lol)

https://www.youtube.com/watch?v=QvpKOogjmPg

 

[knightly]

If the distance form the rear element to the lens is different than the convergence point, you'll lose the ability for infinity focus. FD mounts are ones I learned to avoid when researching adaptors… the adaptors (FD > EFs for mine) needed a lensed adaptor to achieve infinity focus… the cheap adaptors put cheap glass between your lens and your camera… so I don't use my lenses that have mounts that have too short a convergence point. Even the ones that are technically ok to use can miss the exact point based on their manufacturing tolerances.

 

[dmontgom]

Thanks for the input! After reading your response I googled convergence point, etc, and I learned a little more about this stuff and it gave me an idea.

I removed the adapter from the equation (for the record, this adapter has no glass, it's just a tube). I took some video just holding the lens out in front of the sensor but closer than the adapter would allow and I was able to get it to focus further away... so I think my answer may be a thinner adapter.

Here's a screengrab from my experiment... focuses from further away (although very fuzzy due to light leaking in where there should be an adapter... also, now you know what that box lid on my desk is for).

 

[wheatgrinder]

you gotta bad lens.. try and fix it if you want, your not out much if you botch it, which you most likely will.

Let me know if you want to buy one I have a haminex 28mm that Id sell for cheap. I know it works with a gh2 and FD adapter.