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colinM
09-04-2016, 11:28am
Hi All,

Just acquired this Mirror lens for a reasonably cheap price, I know they are soft and hard to focus but I like the concept of long Focal Length and low price. The Lens has all 4 Filters and original case.

My problem is Fungus on front lens.

Has anyone had experience in pulling one of these down.

These appear to be different from the " Normal " Mirror Lenses as they are Solid Glass with no air gaps in the lens.

I have cleaned the rear and was pretty straight forward but the Front is causing some problems.

I can see what needs to be done it's just a problem of how without doing damage.

I do also have a Makinon 500 mm F:8 and a Tokina 500 mm F:8 both cleaned with no problems.

Any advice would be appreciated.

Colin

ricktas
09-04-2016, 1:28pm
Have not pulled one apart, however, how about joining in on the forums. So far all your post have been about you and your gear. How about giving some advice to others, or some CC on a photo or three. If everyone just posted their own stuff and ignored everyone else's discussions, and did not help others, this site would be useless.

ameerat42
09-04-2016, 3:28pm
...Just acquired this Mirror lens for a reasonably cheap price, I know they are soft and hard to focus but I like the concept of long Focal Length and low price...
My problem is Fungus on front lens...

Though I pulled a [brand long forgotten] CAT lens apart once, it wasn't too hard after removing some of the rubber grips.
Dexterity and good eyesight help, and I do not remember there being any of the usual adjusting screws for this type of
optical device. I think the whole construction is "engineered with adjustments in it". But my motivation was different. I expected it to
be good. Instead...

After I got it and had done tests, I realised that it was NO GOOD for photography, so I used it as a small 'scope instead,
at which, strangely, it excelled:confused013. (Hype and sales talk and saleperson ignorance of product.) Since it was of some
use, I decided to keep it, but I told the shop owner about it. (Had I known all this before I would not have got it at all!!!)

I since got a Tamron 500/8, which excelled at EVERYthing. Also, if you're into weights (as this lens acquisition implies) you can
try for the RUSSIAN MTO brand 1000/11. It's not a solid CAT, but it is WERRY TSCHARP (excuse my poor Russian:o). They are 2nd
hand and usually retail for about $250 (and resemble a 2L tin of paint).

Seriously, though. Did you know it had fungus on (presumably the back of) the front element? If so, then your penchant for acquiring
such lenses must be strong. - Or are you considering it for an alternative use as a door stop?:D

ameerat42
09-04-2016, 7:48pm
--Oh! And a front retaining ring...

colinM
09-04-2016, 7:55pm
Hi,

I like them, they are reasonably small compared to the equivalent Focal Length of the current era. I realize that they are archaic, unusable, manual & a waste of money if used in everyday photography.

I new nothing about the Lens except that it had Fungus. I made the assumption that it was similar to others I had worked on. Wrong !!!!!

I know the front retaining ring has to come out but there are no slots or holes to accomplish this with a tool.

I will take a few photos and access the results, if not satisfactory will put it on the shelf .


Colin

arthurking83
09-04-2016, 8:23pm
Interesting lens.

The f/11 aperture will make it hard(er) to focus than most other manual lenses.

Do you keep at least one filter mounted at the rear of the lens?
Most Cats have been designed to focus sharply only when one of the rear filter are mounted.
(had the Tammy version about 20 years ago now, and cant' remember if it needed one too).

Obviously you don't want the ND filter mounted, so the haze filter should be the one you use.
BTW, having such a small aperture and an ND filter to work with, sometimes these things are handy for 'sun watching' too.

Anyhow, did some searching for more info on this lens and an interesting tidbit of info came in during that search.

The guy that designed the lens once worked for a mob called Perkin - Elmer, but the chap moved on to start his own company called OPCON.
OPCON were used to consult in the design and manufacture of this solid cat lens .. as well as the 600mm version too.
But OPCON didn't have the resources to build the lenses(these may be the only lenses that Vivitar didn't make in Japan!) .. so OPCON outsourced the building of those lenses to Perkin - Elmar.

Now that, in itself, isn't strange or weird, but what is (r-e-a-l-l-y) interesting in this tale is ....


.. that Perkin - Elmar were contracted by NASA to build the Hubble Telescope .. and from that one would reasonably be content that the makers of the famous Hubble also made this lens! This lens has a great lineage behind it.
The interesting part in this tale tho comes from the point that it was a monumental mismanagement mistake on the part of Perkin - Elmar that caused the Hubble to be blind for a long time in it's initial history! :p
The corrector lens was misaligned by the techs at P-E which caused the Hubble to not see clearly(and NASA had to do a rescue mission to correct the flaw).

So on the one hand you have a small piece of history in Hubble's little offspring right in the palm of your hands :p .. and on the other hand it's probably badly aligned! :eek:
Just make sure you have the corrector lens fitted to the lens for it to see(hopefully clearer than P-E had the Hubble seeing).

ameerat42
09-04-2016, 8:38pm
...
Obviously you don't want the ND filter mounted, so the haze filter should be the one you use.
BTW, having such a small aperture and an ND filter to work with, sometimes these things are handy for 'sun watching' too.


Sun-watcher here...

Is that ND filter rated at 100,000X and...[other specs]?

No matter even if it is. - A sun filter should be mounted to cover (sometime just "over") the PRIMARY OBJECTIVE.

If not, you won't see much - after initial dazzlement - ever again!

colinM
09-04-2016, 10:56pm
Yes,

Familiar with the Perkins - Elmer connection and the Hubble. Research into the lens indicates that it is the same as the Perkins - Elmer but renamed as Vivitar.

The original Patents cites Perkins - Elmer and invented by Juan L Rayces. Patent granted Dec 6, 1975 so it probably hit the market 2 years later.

The Patent drawings indicate 3 lenses from front to rear covering 100 mm or so, a lot of glass over a short space so it will be interesting to try out when the adapter arrives. PK to F


124934



Colin

arthurking83
10-04-2016, 4:08am
From what I've read these lenses are (supposedly) T-mount.
So if your lens is PK, then just remove the PK adapter and use a T to F adapter.

Many Nikon bodies have protruding leading edges of the built in flash. The lens may just strike it when you mount it, and the common thing to do is to just loosen the T-mount to F adapter.
But this makes the lens a bit wobbly on the adapter, so if you can find a short spacer to fit between T-mount and F mount, and then tighten it up .... this gives you the clearance needed to clear the flash on the body.

colinM
10-04-2016, 10:17am
HI,

I thought it was T mount also, nothing so simple.

In any case not T Mount but PK incorporated into the body of lens. Secured from behind, would require complete strip down to convert. Not going down that path.

Bought online, incorrectly listed as Asahi Optic Co, I think the Seller made the mistake of associating PK mount to Ashai with this lens.

Familiar with the problems of the flash unit, that's why I have gone with the PK to F adapter with glass. This will bring the lens out approx 10-15 mm from the camera, solving the flash dilemma.

I have dragged out my old 70's tripod with screw attachment of lens, not too keen on these quick release tripods. I bought a Tripod several weeks ago that has a Monopod in it, I remove the Monopod section and insert the 70's section and hey presto ..... a stable environment.

Colin

colinM
13-04-2016, 4:04pm
Hi, Just an update,

Adapter arrived, tried a few pics Tripod mounted with 10 sec delay. Pics Ok given the age and technology of the period.
Then switched over to remote via WMU coupled with a 10 in Android. A lot easier to focus with a 10 in screen.

The result ... Local Hospital from approx 5 klms away

Shot at 500, ASA 800 F:11 with UV/Haze Filter in end.

Hospital is at an angle so the DOF drops of towards the left.

Colin

MarkChap
13-04-2016, 4:22pm
At 5km away, I don't think you have a DoF issue, I would be more inclined to say you have a sharpness issue in the corner of the lens, again probably not unexpected with the technology

colinM
13-04-2016, 6:36pm
Hi,

I must admit your conclusion sounds more logical than my assumption. Will investigate further.

ameerat42
13-04-2016, 6:46pm
Definitely agree with Mark that there is no DOF fall-off. This result looks typical of the old lens I had
(mentioned above), and not like the results I used to get with the Tamron 500.

In addition (not necessarily to do with the lens), the sky shows unevenness of processing - by way of banding - where swathes of sky
are all the same brightness level. You will see this more if you adjust the levels so as to darken the mid-tones and darker tones.

Back to the lens, it could be my perception, but it seems that the LHS is fuzzier than the RHS, with the middle being the "sharpest".
This could be a case of misaligned optics. A more useful test might be to shoot a grid at about 10-20 metres away from the camera.
If not that, then a page of text. But make sure that it is flat and fairly even.

arthurking83
13-04-2016, 7:01pm
You'll be surprised at how shallow DOF can be with a very long lens.

You have a better focusing system than the viewfinder in the 10" tablet screen, or Lv mode to see this for yourself too.

The issue is that the lens is obviously not as sharp as the more modern lenses are capable of, couple that to heat haze(over such a long distance), almost certainly vibrations from the tripod(unless it's anchored to a large boulder) .. they all add up to render sharpness deficiencies, and it's easy to just assume that the lens is not sharp, for example, in the corners or whatever.

There's a 99.9% likelyhood that the adapter is the culprit to the soft rendering, both in the correcting glass and the quality of the adapter itself too.

Some things to check out or try:
I'm guessing that the adapter probably has a removable correcting lens?
if so, try to see how far into infinity the lens can focus on your Nikon.
Even tho the Pentax format has a slightly shorter register distance, it's not by much(0.5mm or something .. off the top of my head).
Most of these old timer long lenses have the abiliy to focus beyond infinity .. designed so for various reasons.

If this lens can focus beyond infinity by just enough, then even taking into account the added distance of the PK-F adapter and that the PK mount has a shorter register distance, you may find that it 'may' just focus to infinity to get you by.

FWIW: I have an M42 lens from a few hundred years ago(or close to it). M42 is a Pentax system, so has the same register distance as the PK system.
I just got a simple M42-F adapter, which is very thin, and tried to focus to infinity. But this particular lens doesn't focus past infinity! It hard stops at the infinity mark.
I pulled the lens apart and used a file to just nip out a shaving off the ring on the body that hard stops the lens at infinity .. ie. allowing the lens to focus just past infinity.
Put lens on the Nikon's and voila! .. focus to infinity on a Nikon body.
The point is that it didn't need much to do. I'm not suggesting for you to mod the lens(but if I were you I would anyhow! :p) .. just test the lens to see what's possible.

How many mm's does the adapter force the lens out from the body?
M42 - F adapters are literally only a mm or two at most. I dare say that a PK to F adapter is probably a bit more(eg. 5mm) which may be an issue with all of the above).

ps. is that the entire frame, or a crop?

Try focusing in on something a bit closer(say 10-20 or 30 meter's or so) reduce the impact of heat haze at the least.
You can't do anything about mirror slap on a D3300 either, and that's almost certainly going to be an issue in many situations .. even possible at shutter speeds of 1/500.

colinM
13-04-2016, 9:28pm
Thanks for sharing your expertise in my exercise in futility.

I must admit that I am still coming to grips with the right combination of speed & ISO. It's been 40 years since I hung up the old SLR.

The original image has the same problem, I resized to 1200 x 800 to conform with upload but the image as posted has been cropped. I presume by the Forums Image Manager or equivalent.

Will try all contributors suggestions and go from there.

Will probably put on the shelf as a piece of History and buy a proper lens.

ameerat42
14-04-2016, 8:12am
Thanks for sharing your expertise in my exercise in futility.

Not really. Good to try, and the ?fungus on the elements might be beating you.:confused013
Since you've got a few lenses like this you could try each out on the same subject and compare
the results with a more modern lens.


The original image has the same problem, I resized to 1200 x 800 to conform with upload but the image as posted has been cropped. I presume by the Forums Image Manager or equivalent...


I checked via "Image Info" and it is still 1200 x 800 pixels. No such cropping or any other manipulation occurs if it conforms to the size restrictions.
If too big, it doesn't load, and you get a message to that effect.

colinM
14-04-2016, 2:24pm
Well, after taking 30 photographs of charts 25 metres away, with and without glass in adapter, this lens is going on the shelf.

The Fungus is no longer a problem as was cleaned out several days ago.

Just tooo hard to consistantly focus, I might use it as a spy glass.

The Sigma 150-600 is looking pretty good at this stage.

Who knows, with a comparatively good lens I may be able to contribute to the Forum with some reasonably acceptable photographs.

Colin

arthurking83
14-04-2016, 4:36pm
......

Just tooo hard to consistantly focus, I might use it as a spy glass.

.....

Damned straight! all long manual focus lenses are.

If you're keen to tinker a bit, you can get a Dandelion chip for it.
It 'should' be relatively easy to attach the Dandelion chip to the adapter, as it's an adapter not a lens. It may need to be modded a little to make it seat nice and secure.
What the Dandelion(DL) will do is give you metering, which is handy but not essential, but more importantly it gives you focus trap mode too.
You can get other CPU's to enhance your manual lenses, but why I got a DL chip instead of the sometimes better other CPU chips was for this focus trap mode.
Focus trap is a pseudo AF, but manually focused method of focusing manual lenses.
The way it works is that you set the camera to only expose when the image is focused, while the image is defocused you keep the shutter release down all the way. It won't expose as the image is defocused. As soon as the image is focused(using the rangefinder/green dot for confirmation), the camera then takes the shot .. ie. much quicker than you can using the rangefinder or by eye.

I mounted a DL to my 500/8 mirror, and while it was new and it worked, the focus trap was 'awesome' .. in that it(not me) focused spot on .... every shot. As long I held the camera steady, images were all focused well.
Problem with the DL on the 500 mirror was that the only and really easy way to mount the chip was to simply glue it to the rear filter. It's a 99.9% perfect fitment there and it worked for a while.
But that 0.1% imperfection in the overall design and mounting was the downfall of the chip. Every time I mounted and unmounted the lens the chip would be damaged ever so slightly more .. to the point where it totally collapsed in on itself. If the 500 was only ever used on the one camera and never removed, the chip would have been fine.

At $30ish for a DL chip, it was worth the effort and monetary wastage to see how it worked.

On the topic of the forum rules re image sizes, the site doesn't crop the image(that I know of or have ever experienced).
It may resize the image, but not crop AFAIK.

As far as long lenses and image quality .. the more modern, even slightly cheaper lenses will provide better overall image quality than these expensive old timers ever could.
I don't use my old timer 500 mirror, or 300/2.8 for the best IQ achievable .. that would have driven me stark raving mad a long time ago .. I just like the challenge of capturing usable images and the challenge of using them .. ie. a bit of fun

colinM
14-04-2016, 5:28pm
Hi,

I did look into the DL chip about a month ago for another lens.

I gave up on reading a similar experience to you, combined with a rumor that the Firmware of D 3300 doesn't allow it, " No lens attached " and not being able to program it.

The 800 mm will probably be used for experimenting and playing around.

Colin