[voyager13]

Hi Guys

I am using a Kx and a SMC Takumar 50mm 1.4 which is a legend in Takumar circles. Now the 'problem' I have noticed is that I am not able to focus on my subject beyond say 10-12 inches at max zoom. Beyond that range it gets pretty blurry. Within that range the focus is sharp(f4) and the photos come out superb. Is that normal for this lens?

When I use my other Takumar 55/1.8 on the same camera, I can focus from a good 3 feet on the subject. Since the focal lengths of the two lenses are somewhat same I was wondering if it is normal for the 50mm lens to not be able to focus at longer distances as the 55mm lens does. Any idea what's happening?

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Last edited by voyager13; 05-27-2012 at 08:57 AM. Reason: Forgot something

[Adam]

Do you have the flanged adapter that prevents you from focusing at infinity?

[voyager13]

No its not the flanged adapter (I know which one you mean )
The same adapter allows other lenses to focus to infinity.
Forgot to mention that I put the 50mm Tak out on the windowsill for 2 days to get the yellowing away. It got hit by strong sunshine those two days for a couple of hours each day. Could that have affected the performance? If so, than why does it focus brilliantly at all at a shorter distance?

[jatrax]

Could that have affected the performance?

No that could not possibly have affected it.

Is this a new to you lens? And did it ever focus properly?

Does the focus ring turn through the entire throw? That should be about 180 degrees on that lens.

At infinity focus the lens should be fully retracted, there is a small change in diameter of the lens barrel about 4.5mm in, this should be almost in line with the focusing ring when retracted properly. When focused at minimum, (turn the focus ring all the way to the left facing the rear of the lens) the distance scale should read just on the "4" of "0.45". The lens should now extend approximately 12.5mm from the front of the focusing ring.

[voyager13]

Its a new lens to me though that shouldn't matter as I can focus manually well I haven't used it for a while as I have been using other lenses but as I remember it focused clearly at full zoom, which its not doing now. The focus ring does turn the 180 degrees as you mentioned and the distance scale reads 0.45". It does fully retract at infinity also. Any other suggestions?

[jatrax]

Its a new lens to me though that shouldn't matter as I can focus manually well

I was trying to find out if you just got it and maybe it was not ever working, not trying to disparage your manual focus skills

So it focuses properly at 10 to 12" but not beyond that? That seems odd as the minimum focus distance on that lens is about 17". Or did I misread something?

Also you say "at max zoom" I assume you are talking about the maximum throw of the focus ring? Because that is not a "zoom" lens.

Takumars can have their focus thrown off because the focus range is adjustable by loosening a few screws. These can come loose and then the focus gets off. But what you are talking about seems very extreme, I am not sure there is that amount of adjustment in it. If I understand what you are saying at infinity focus you can focus at 10 - 12 inches but everything beyond that is blurry?

[voyager13]

I am not so well conversant with terms like max throw as I am still learning the ropes, so apologies if I have unknowingly interpreted otherwise. As you mentioned the min focus distance of this lens is about 17", it does focus at around that (and not at 10-12" as mentioned earlier). If that is how it should be for the 50mm 1.4, than how is the focus distance of the other Tak 55mm 1.8 much more than the 1.4? Shouldn't it be somewhere near to 17" also?

[RioRico]

'Zoom' is changing focal length. 'Throw' is changing focus distance, or rather how far the focus ring can be spun. That's OK, learning photography is like being in a language class. There are always more words to learn.

Per the specs, CFD (close-focus distance) of both the Super Takumar 50/1.4 and 55/1.8 are ~45cm from the frame (the film or sensor plane). I just measured mine and I get the same number, about 44cm / 17in. Throw on my 50/1.4 is about 240 degrees or 2/3 of a full spin. Throw on my 55/1.8 is about 270 degrees or 3/4 of a full spin. I just checked those too. If your lens doesn't spin that far then there's a real problem.

And for comparison: Total throw on my Macro Takumar is roughly 300 degrees or 5/6 of a full spin. But throw from 2m to infinity is only about 60 degrees or 1/6 of a full spin. That makes careful focusing at a distance pretty tricky.

[jatrax]

so apologies if I have unknowingly interpreted otherwise.

No apologies are necessary, I just want to make sure we understand each other. This is an international forum and for many English is not their first language so it only makes sense to be sure each party understands.

That said, I am not sure I understand your problem. Both the 55mm and the 50mm have the same minimum focus distance. That means no matter what you do (well, without adding extension tubes but that is another story) you will not be able to focus on anything closer to you that 17" (45cm). They should also both focus to infinity. There is no maximum focus distance because infinity is, well infinite.

Anyway are you saying you cannot focus closer than 17" or farther away than 17"? Turn the focus ring to the infinity mark, that is sort of an "8" on it's side and look at something very far away, miles away. It should be in focus. Find something about 10 feet away and set the lens to the 10 foot mark on the focusing ring, it should be in focus or nearly so. Are you saying this does not happen?

[MegaPower]

From what I remember, if you cannot focus to infinity, you will be able to focus closer than 0.45m. (More macro)
If you cannot focus close (to the spec 0.45m), you will be able to focus pass infinity.

I did my calibration on my Takumar 50/1.4 and found this is interesting.
May be you can try to adjust your lens.

[voyager13]

RioRico - Lot of technical stuff that I have to sit in a quiet room and think about. Takes time but I will try to understand what you wrote

Jatrax - When the ring is at infinity I cannot see anything clearly through the VF, but when it is at 10 ft mark I can see nearby objects(about 17" away) tack sharp. Shouldn't it be focusing sharp at infinity as well like you mentioned and just like the 55/1.8 does? If so,is there anything that can be done to correct that?

MegaPower - How do i adjust my lens besides turning the usual focus ring and moving physically to get the object into focus? Do you mean to physically do calibrations on the lens? If so, I would probably end up messing it as I have never done that before to a lens.

[voyager13]

Throw on my 50/1.4 is about 240 degrees or 2/3 of a full spin.

RioRico - What did you mean by that? Is it that the focus ring should rotate 240 degrees when fully spun? Mine rotates 180 degrees 1/2 on the 50/1.4

[MegaPower]

You have to open up the lens.

If you can assess to some tools that can open up the "name ring said takumar 50mm" on the front.
Then you will see three screw. Loose up the three screw and you can calibrate the focus.

[voyager13]

MegaPower - I may give it a try once I am sure the lens is no-good. Will wait for Jatrax and Rio to respond. What are these tools that can open these lenses called on ebay?

[RioRico]

Throw on my 50/1.4 is about 240 degrees or 2/3 of a full spin.

RioRico - What did you mean by that? Is it that the focus ring should rotate 240 degrees when fully spun? Mine rotates 180 degrees 1/2 on the 50/1.4

Then yours isn't spinning as far as it should. I'm afraid it means opening the lens for reconstructive surgery. Follow @MegaPower's suggestion. And look for out-of-place bits that may interfere with the focus.

EDIT: I know there have been past threads here about opening this lens. I haven't done that -- I only glued mine back together! I modify lenses, I don't repair them. I've got to sign off now, but if a solution hasn't arrived by morning, I'll try to dig up the repair threads. G'night.