20cm super yashinon 1:4.5 weird behaviour

[Rusty]

just received the lens and did some test shots
The first image looks ok
Then shot an abelia bush against a brighter background to check boheh and highlights wide open (on tripod)....all as expected ok
stopped down to f22 and did same shot and it flares
Shoud'nt stopping down inhibit flare and not the other way round ?
What is going on?






I repeated the test by taking an image of the corner of the roof of the house and the results were even worse at f22

[PaulC]

Lens hoods control flare by reducing stray light getting into the lens. I believe longer exposures (which you would get at smaller apertures) can increase it. I suppose it is possible that the aperture blades themselves might be acting as an additional reflective surface, increasing the internal reflections.

It would be interesting to shoot at different apertures while adjusting the ISO so that the exposure times remain constant. That would tell you whether the flare was a result of exposure times or was increased in some way by the iris itself.

[peterqd]

My Jupiter 21 does that too. Someone said it has to do with sensor flare so that it happens on a DSLR but not on a film cam, but I haven't tried.

[PaulC]

I doubt that it is the sensor. Sensor flare is described as creating little rainbow patterns or banding in high contrast areas, neither description fits this.

[Rusty]

@ Paulc..Thanks That's an interesting thought,will do some tests on full manual and regulate exposure by manipulating iso
shining a point source light into the lens from either side give some reflections of the slightly worn parts of the iris , but difficult to say if it can have such drastic effect ,and only at f22 the reflections are visible from f5.6

@ Peterqd.. Thanks Peter..Is the sensorflare that you mention related to bloom or is that totally something else?

[luisalegria]

Which Yashinon is this ?

There is a fairly rare automatic Yashinon 200/4.5 made by Tokina I believe, also sold by Ricoh for a short time. If you are having quality problems that may explain its rarity.

The other one is much more common, also made by Tokina, but its a preset and I have seen this sold as a Yashinon-R, not a Super-Yashinon. I have a version of this and I have seen no flare.

Could you post a picture of the lens ?

As for problems at f/22 - this is very likely. Not all lenses are very good stopped down this much.

[Rusty]

Hi Luis
Here are images of the lens
Something unusual to ne was that the lens came with a drop in rear filter (kodak made skylight), never seen that on a 200mm

[peterqd]

[Rusty]

@ Peterqd

I Did some more shots.... exactly the same result as what you posted
It looks like a total loss of contrast from 5.6 getting worse as you stop down , starting at the center of the lens

Mine even flares with the sun almost 90 deg to the lens axis
....opened it up and cleaned all surfaces but no improvement
one lens for the bin maybe

[Attila]

Good for collectors, pretty rare.
I wasn't satisfied with my Yashica ML 135mm (cosina made) and Yashica ML 200mm too. Shorter focal lengths Yashicas are great ones anyway.

[peterqd]

[Rusty]

@ Peterqd
I am going to give it a try Holding the backend of the lens against my eye and pointing it towards the light , there is reflections of the insides of the barrel (as if the black paint is not matte enough) the barrel lights up light grey where the light hits it
Any advice on paint to use ? maybe ordinary schoolblackboard paint applied with a small brush?

[Rusty]

[Attila]

No idea unfortunatelly! Luisegaleria and Koji our expert in this field, this is a rare lens, very rare I think. Keep in big respect if you don't want to keep please ask them first , perhaps missing lens form their collection.

[Rusty]

Thanks Attila ...will wait for their replies

[luisalegria]

Hi Rusty,

Yes, its a Yashinon-R, of the first series of Yashinon lenses made for their SLRs. Actually made by Tokina/Tokyo Koki. Its a very common lens, as it was sold under many brands. It is uncommon under the Yashinon brand though, as it was sold only in the early days of the Yashica SLR business, there are sure to be collectors looking for it.

I have the same lens sold under a merchants brand.

http://forum.mflenses.com/lentar-tokina-200-4-5-preset-another-lens-of-many-names-t11353,highlight,lentar.html

Mine doesn't have a flare problem, and I never heard of this problem with this lens. It could be an unfortunate interaction with this particular combination of DSLR and lens. Or maybe it's a problem with the drop-in filter - mine doesn't have that.

[Rusty]

Thanks Luis

The shots were taken with with the filter removed, so i will start with reblacking the interior and then go from there
I have to keep my lens collection larger than my "useless lenses box"
The latter is growing fast!

Thanks once again
Daniel

[Rusty]

One last image from the flare generator before i take it apart
overcast and rainy,min focus distance at iso 200 5.6 on 20D
Hope i can rescue it from going to that lens box

[wariag]

[wariag]

[Rusty]

@ Wariag

I tried to clean it as well as possible, there is still some oily residue on the extreme perimeter of the glass against the metal, the lenses are recessed quite deep into the barrel and difficult to clean

I'm still scraping together courage to dismantle, in fear of disturbing some lens alignment

[wariag]

[Rusty]

Thanks !will try tonight...it is not much use with the flare anyway
if something goes wrong ...nothing lost really
just more spares gained