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06-16-2012, 01:02 AM   #1
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Manual lensen on K-5, a few newbie questions

Hi fellow pentaxians,


relatively new here, but this forum has been a goldmine of information to me in my first few weeks of owning a K-5. I've been getting fascinated by the possibility of using used manual lenses on my camera and the last week I have bought a few lenses on eBay for next to nothing. (don't want to spend top dollar just yet).

I have a few small questions which I haven't found on here yet (maybe I haven't looked well enough).

1- the q-tip/ballpen tube trick for the Helios lenses, I haven't gotten round to trying it yet, but it seems straightforward enough, I was wondering just one thing: should the little tube grab/squeeze the pin? The ones I have seem to be slighty bigger than the pin, but I guess there is a larger piece at the end of the pin (on the 'inside' of the lens that holds the tube in place? just want to clear this up before I start to open up the lens. Also, I need to buy an adapter, I guess ideally I buy an original Pentax adapter for my M42 lens? I've already ordered a 3 dollar one before I started reading up on the M42 lenses here, but I'm looking out for an original too. Any pointers to get one of those here in Europe are welcome.

2- I've bought a cheap 70-200mm zoom lens. (10 dollars including shipping, but it seems to be working well enough). When I mount the lens on the camera and then turn it on, the camera asks me for a focal lenght. Which one should I select? I've noticed on a 135mm lens that when I select 120mm on the camera, it's much easier to focus. What would be the ideal selection on a zoom lens, or is it a case of trial and error?

I had some more questions in my head earlier, but they've gone for the moment, I post when I remember, thanks for your help.

06-16-2012, 02:43 AM - 1 Like   #2
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1. Not all Helios lenses need the pin modification, only the 44M-something. The 44M, 44-2, 44-3, which are also the most common, either have an A/M switch that allows you to close the aperture, or a preset aperture altogether. If you haven't bought any Helios lens, I'd suggest you to search for one of the above 3 models, or any K-mount variant if you can find. Adapter-wise, the $3 you ordered probably is the non-infinity kind. It has the advantage of being easy to mount-unmount, but it only allows you to do portraits and close-up shots, which might be ok.
2. How come is it easier to focus when you set a particular focal length for the shake reduction system? Are you sure it's not placebo?
I don't use zoom lenses, so I can't help you here, but I'd simply turn SR off, because I had a situation where incorrect focal length data introduced some strange blur in the image.
06-16-2012, 03:30 AM   #3
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Have a read here:

https://www.pentaxforums.com/forums/pentax-beginners-corner-q/110658-using-ma...x-dslrs-f.html
06-16-2012, 05:14 AM   #4
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The modification for auto only lenses does not require the tube to squeeze the pin, the idea is to cut the tube to a length that blocks the part holding the pin at a distance that leaves the aperture in the control of the ring. You will see when you push the pin that there is a part attached to it. The tube goes between this part and the base of the lens that the pin goes through

As for focal length settings for MF zooms, there have been more discussions on this than you can imagine. I have the approach that I enter the lowest focal length if it is for general shooting, or the longest if I know I am always using it at maximum length.

06-16-2012, 06:15 AM   #5
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ok, thanks a bunch, obviously it should be lenses in topic title, but I can't seem to edit it.

I already have the helios here at home, it's 44m4 in pristine shape as far as I can tell, without an A/m switch. I just need to find a screwdriver that fits the screws to start the modification. The adapter is indeed one of the non-infinity type's, I'll have a go with that one first and see what happens.

As for the choice of focal lenght. I'm pretty conviced that the Pentax M 135mm F3.5 lens, focuses a lot easier and sharper when I choose 120mm upon starting up the camera. I'll try to set it up on a tripod and take some test shots...
06-16-2012, 06:19 AM   #6
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Ok then, pay attention not to remove the aperture ring, it will be a pain to mount it again with the ball bearings in place. But simply do not disturb it and it will be ok. As far as I'm concerned, almost any flat screwdriver is ok for those screws, as they're not precision type?
Also, for tripod work, shake reduction should best be turned off, and it automatically turns off too when using the 2s or 12s timer option. I really fail to see in what way would a shake reduction system set to incorrect focal length help you focus easier, except, as I said, psychological.
06-16-2012, 06:26 AM   #7
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The reason for entering the focal length at startup for manual lenses is to let the SR system know how much correction to apply.
Theoretically this should not affect focusing but it might have an impact on motion induced blur.
Note that when shooting from a tripod with 2 second delay setting the SR is automatically deactivated.
So in this case focal length entered will make no difference.
YMMV.
06-16-2012, 06:30 AM   #8
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ok, kind of dumb of me to try out something that has to do with SR on a tripod, you live and learn...

06-16-2012, 06:43 AM - 1 Like   #9
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As mentioned, SR is for handheld shooting only. If the camera is set for any timer delay, it shuts off SR automatically. But if you have the camera immobilized, whether on tripod or desktop or on a wall or whatever, and you're NOT using a timer, turn it off anyway.

What to tell the SR'bot? Tell it the actual focal length (or as close as possible) of the lens you've mounted. MF zooms are tricky. I've tried entering the mean or a weighted mean, but that usually sucks. I have found it best to either:

1- set the zoom and tell the SR'bot just one focal length, and stay there; or
2- tell the SR'bot the actual focal length every time the zoom changes; or
3- switch SR off and shoot tripodded, or in good light with a fast shutter.

I usually pick door #3. I have a zillion lenses, and the SR problem is why only 5% of my lenses are MF zooms. If it isn't among the best of zooms, I sell it.
06-16-2012, 07:10 AM   #10
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some shots taken with my newly acquired manual zoom lens (TOU/FIVE STAR 75-200mm F/4.5), bought from Israel for about 2 euro's I think it delivers reasonable results if you're not looking to print or enlarge the photo's. All shot handheld with a variety of settings. No post processing, only resized for uploading...
TOU/FIVE STAR 75-200mm F/4.5 - a set on Flickr
06-16-2012, 07:38 AM   #11
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In addition to the excellent comments so far, I just wanted to mention that for zoom lenses, the "seventh" pin on newer zoom lenses is what tells the body the current zoom setting, and in the case of variable aperture zooms, the current (wide-open) aperture. The seventh pin came along with the KAF lens mount designation and later, but is not available on KA and earlier. There are some other things that are also provided by the seventh pin on both primes and zooms. But for zoom lenses, support for the current zoom setting and current aperture are items that can make a real difference in daily use.

I discovered this myself when a friend loaned me an earlier zoom lens and it got real annoying, having to tell the camera what focal length every time I mounted it. This annoying step is true for older primes as well, but at least that problem applies only once when you switch lenses, rather than having to guess at some average focal length I am going to use.

Also, it is kind of nags me psycologically that the true aperture can be off by a stop or two from what the camera thinks, depending on focal length. I should mention that the lens was a KA mount with the first six pins. If it were a K mount with no electrical contact whatsoever, then this wouldn't be a problem.

Anyhow I decided to give the lens back to my friend. (And he is still my friend.) Shoot with whatever you have.
06-18-2012, 08:42 AM   #12
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just performed the q-tip adjustment, piece of cake, it took me more time to find a suitable screwdriver than to actually do it. Can't wait for the adapter to arrive...
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