I'm really surprised with Alf's image samples vs yours Jim. Chroma is definitely present, I think it could be partly with the lens design.

I was chatting with Jim regarding conversion of the 50mm 1.2L FD

Like the 50mm 1.2 SSC aspherical The rear element is considered the "floating" element. This element is crucial to retain the sharpness and reduce chroma on the aspherical FD lenses. Problem is on how to mount this.

I'm still trying to find a solution. I was thinking machining off the rest of the rear element mount, but the question is how much. I don't currently have the time to keep experimenting with it. But, I figured it anyone dares attempt to convert FD mounts to be aware of the difficulty.

I posted some test shots I took without the rear element below.




Here's it mounted on my 5D. It does go over infinity so a spacer needs to be added.

JimBuchanan wrote:


As per suggestion of tmessenger in the above issue of “pink fringing”, to eliminate any flare or reflections caused by light bouncing around the mirror box with wide apertures, or brighter scenes, or closer distances where the lens assembly moves out front and exposes the stock chrome threads of the M42-EOS adapter, certain areas were painted flat black to eliminate reflections.

JimBuchanan wrote:
An addendum to this thread shows a refinement of my method of Canon FL 55 1.2 lens conversion. As I was hired to convert another lens, I took the opportunity to turn down the helicoid assembly as described by Alf Beharie. The benefit of this is not only better precision, but eliminating the need of a spacer between the lens and m42-EOS adapter, and not having to mess with the helicoid mechanism at all.

Shown, is the rear of the helicoid assembly and M42-EOS adapter, after 2mm was removed. The infinity focus stop is also seen with the 3 slot screws, and was ultimately used to fine tune infinity.

manowar wrote:
I have both of the lenses, FL and Rokkor. Didnt have a chance for a proper test but from the results taken from both lenses, the Rokkor is obviously much much far better than the FL55, IMHO.
Sorry to say but I found nothing amazing from this FL55 but it's still a keeper.

So far, I have'nt seen a single sample from the Rokkor where it shows any gain in IQ over the FL...I wonder if you are using your FL via one of those IQ reducing FL/FD-EF optical adapters?...That would explain the poor results you are getting with your FL. Would it be possible for you to post some head to head comparison pics?

the FL seems to have a lot more coma wide open, at least.

Interesting work. I am still trying to remove the front trim ring to get at the infinite stop, with no luck. Are you guys using any special tools, because it doesn't seem like it will budge. Thanks much.

I use a plastic pvc pipe with a rubber inner tube over the end of it. This will give you enough traction on the trim ring to get it to turn loose.

tm

I'm getting OK results with my FL55 wide open.

tm

Ed Sawyer wrote:
the FL seems to have a lot more coma wide open, at least.

Few snaps bokeh test

tmessenger,
I'd say that that is more than just ok results. It looks very much like rokkor sharpness to me and it certainly has smooth bokeh!

Holding my un converted FL 55/1.2 infront of my 20d gives results that look every bit as good as my rokkor. Infact i have a suspicion that with my particular copies the FL is actually the better performer... it certainly delivers more consistant results throughout the f stops.

not bad for a lens I paid US$65 for with a 'free' FT QL...

just my 2p

Here is canon fd version


Minolta



Alf please understand - Sigma sd14 Foveon gives that character that you have with your canon lense.
On 5D perfomance of this canon lense is not stellar

http://www.flickr.com/photos/convert1/page2/

The other thing i am not using rokkor 58 1.2 on Sigma anymore - the reason is simple - f1.2 on such crop 1.7 useless instead i have converted minolta md 50mm f1.7 and will do minolta md 35mm f1.8 convertion.

Dim.ka_, do you have the other pages to these lens tests? Canon FD 50L, for example? Or, the FD 50/1.2 aspherical?

Yes i have the whole test, but there are no other canon lenses.

Dim.ka_ wrote:
Here is canon fd version


Minolta



Interesting charts. Is the 55mm f1.2 SSC listed the aspherical version?

Alf please understand - Sigma sd14 Foveon gives that character that you have with your canon lense.
On 5D perfomance of this canon lense is not stellar

http://www.flickr.com/photos/convert1/page2/

The other thing i am not using rokkor 58 1.2 on Sigma anymore - the reason is simple - f1.2 on such crop 1.7 useless

Why do you think its useless?

The rear lense is so big in diameter that you can not see any difference between 1.2 and 1.8 - from f2 you can say that aperture blades start working.
So decide to convert smaller lenses. Already done MD 50mm 1.7

Good luck, Dmitry. Show us some images with that 35 Rokkor when its done

I've done 2 of the MC Rokkor-HH 35 1.8s, it's a nice lens. haven't done the smaller MD version yet.

Another one I was thinking of was the vivitar 35 1.9. It came in several mounts, some of which probably don't even need converting.

-Ed

ovredal73 thanks, well, this small 35mm MD version will sit on sigma sd14.



For 5D will go this one HH version

Alf Beharie wrote:
manowar wrote:
I have both of the lenses, FL and Rokkor. Didnt have a chance for a proper test but from the results taken from both lenses, the Rokkor is obviously much much far better than the FL55, IMHO.
Sorry to say but I found nothing amazing from this FL55 but it's still a keeper.

So far, I have'nt seen a single sample from the Rokkor where it shows any gain in IQ over the FL...I wonder if you are using your FL via one of those IQ reducing FL/FD-EF optical adapters?...That would explain the poor results you are getting with your FL. Would it be possible for you to post some head to head comparison pics?


Alf, for your own credibility on the forum you are almost required to get yourself a rokkor and shoot it side by side with your great copy of the FL. Thus we all can see what you see. I do not question the greatness of the FL but I do question the claimed superiority of the FL over the Rokkor.

Did the Rokkor bully you in your younger days?

Kind regards

Andreas

Dim.ka wrote:
For 5D will go this one HH version


This Minolta 1,8/35mm HH is a great lens, I already converted it and works very well on 5D.
http://www.flickr.com/photos/convert1/

Kind regards

Nice shots, Convert! I like this lens a lot too, have converted a couple so far. I don't have a shaved mirror so it does hit @ infinity, but I can get out to 20-30ft without hitting.

-Ed

Hi Ed, to get infinity with 1,8/35mm HH was not easy for me (protrude more than Rokkor 1,2/58mm), it means you have to shave the mirror on 5D more than normal".

Kind regards

Convert, that is a serious amount of work converting all those lenses! Impressive

ovredal73 wrote:
Convert, that is a serious amount of work converting all those lenses! Impressive

I appreciate your kindness, a lot of work was behind all the lenses which I converted.

http://www.flickr.com/photos/convert1/
Kind regards