[ankurbbhatt]

Hi All,

I am new to DSLRs and have been buying film era manual lenses (Rikenon 50mm/1.7 K mount, Ozunon 28mm/2.8 M42 mount, Vivitar 200mm/3.5 K mount and Sun 35-200/3.8-5.3 P/K mount) to work with my Pentax.

I am really happy to see that my 2012 made K-5 works with a 1984 lens. This shows how much of a responsible company Pentax as a DSLR mfg company is. Now, my small little question,

1) What focal length should I feed into the K-5, when I mount my K mount manual 35-200 Sun made lens? I mean should I switch the camera on and off several times if I change focal lengths for different photos. Boy, that would be some task to do on this heavy lens-camera combination.

What is the importance of putting the right focal length for manual lenses?

Thanks in advance...

Cheers,
Ankur

[alwaysjerricky]

Actually the reason for putting in the focal length is so that it can help with the in-camera share reduction. So for example, a 50mm prime lens will require a bit more stabilization than a 28mm lens, since the latter is wider. If you find it a hassle to keep changing the focal lengths, you can switch off the SR, it works fine too.

[manishved]

Been there done that...finally ended up with newer AF lenses. Moreover, the optical coatings of older lenses do have limitations when used with modern day DSLRs....

[ankurbbhatt]

Thanks guys for your time and suggestions...My question is still un answered about what to feed my K-5 for the 35-200 zoom? If it is for Shake reduction then putting the 200 mm length will increase shake reduction capabilities which should be a good thing even if I am taking a photo of anywhere between 35-200 mm.

I am looking for more expert opinions !!

Thanks in advance....

[nanhi]

Thanks guys for your time and suggestions...My question is still un answered about what to feed my K-5 for the 35-200 zoom? If it is for Shake reduction then putting the 200 mm length will increase shake reduction capabilities which should be a good thing even if I am taking a photo of anywhere between 35-200 mm.

I am looking for more expert opinions !!

Thanks in advance....

Ankur, I feed a value appox midway between the 35 - 200 mm setting. So in this case I set 100 when the setting menu appears on the LCD. Since the longer end of the lens is more prone to Shake, and if you use this end more often on your zoom lens, then you can even set it to 150 mm.
Hope this helps.
Regards.

[Stone G.]

I mean should I switch the camera on and off several times if I change focal lengths for different photos. Boy, that would be some task to do

Not quite so complicated: If you will, you can go into the recording menu,p. 4 - i.e. without turning your camera off - an input the focal length whenever you change the zoom setting. While you may not really need that for SR purposes (cf. post above) it may sometimes be nice to have the proper focal length recorded in your EXIF data.

[VisualDarkness]

I would rather set it to the widest setting, if I'm about to zoom back and forth with the lens, and lose effectiveness at the long end but don't risk over-compensation SR at the wide and.

[kkoether]

What I found when using my old manual zoom was I would get much sharper pictures turning off SR and keeping the shutter speed 1/500 or higher. If you set the focal length for anything other than the ACTUAL focal length you are shooting you won't get as sharp a picture. The SR will actually blur the picture. SR and panning also don't always play together well in my experience.

[Canada_Rockies]

Keith has the right idea. Shake reduction is great when/if it works, but is really a new idea. On 35mm the rule of thumb was 1/shutter speed as a minimum: 1/200 at the long end of your zoom, for example. I find that 1/300 is better because of the greater magnification on the APS-C sensor. There is no harm using that shutter speed at the short end, either. Keith's idea of 1/500 would be fine, and I would raise that if shooting fast action.

Setting the SR focal length does let the camera record the focal length you used, but can be misleading when you look at the pictures later, unless you are very anal about keeping it up.

[meeverett]

1) What focal length should I feed into the K-5, when I mount my K mount manual 35-200 Sun made lens?

I generally handle this much the same way kkoether and Canada_Rockies are advising. That said, Pentax/Ricoh offer the following: "If you are using a zoom lens, choose a focal length close to the midpoint of the zoom range of the camera."

I would get much sharper pictures turning off SR and keeping the shutter speed 1/500 or higher.

On 35mm the rule of thumb was 1/shutter speed as a minimum: 1/200 at the long end of your zoom, for example. I find that 1/300 is better because of the greater magnification on the APS-C sensor.

I prefer this way, because it avoids the possibility that the SR is working against you, but if I am really set on using SR, I reset the actual focal length I'm using in the SR every time I zoom in or out. Of course, I typically shoot zooms more like I do primes anyway, so I don't usually need to change it much.

[ankurbbhatt]

Thank you all, I like the ideas you have posted. I will definitely try each of them and will post feedback on how it went.

Now, I probably know why my 50 mm/f1.7 Rikenon XR produces blurry images when I shoot at shutter speeds of around 1/10- 1/25. I do not like to crank up the ISO too much and mostly keep it near 100-300 range even in indoor settings in daytime. I would prefer wide open apertures, smooth bokeh images over smaller aperture and more depth of field in order to highlight my subjects especially the portraits.

I will try mid range focal length and see how it goes with the Sun 35-200 f/3.8-5.3 and post photos if I get some nice ones.
With the Rikenon I will now always follow 1/focal length option i.e. 1/50-1/200 shutter speed at least..With SR off and SR On and post photos.

Thank you all again...

Ankur..

[kkoether]

Thank you all, I like the ideas you have posted. I will definitely try each of them and will post feedback on how it went.

Now, I probably know why my 50 mm/f1.7 Rikenon XR produces blurry images when I shoot at shutter speeds of around 1/10- 1/25. I do not like to crank up the ISO too much and mostly keep it near 100-300 range even in indoor settings in daytime. I would prefer wide open apertures, smooth bokeh images over smaller aperture and more depth of field in order to highlight my subjects especially the portraits.

I will try mid range focal length and see how it goes with the Sun 35-200 f/3.8-5.3 and post photos if I get some nice ones.
With the Rikenon I will now always follow 1/focal length option i.e. 1/50-1/200 shutter speed at least..With SR off and SR On and post photos.

Thank you all again...

Ankur..

Another thing I'm figuring out is when shooting in RAW don't be afraid to underexpose several stops to get the shutter speed you want. You can bring the exposure back up in post processing. This was a flash shot that was underexposed and brought back in post processing. The same can be done with any shot within reason.


Before



After



Just another trick to try.

[meeverett]

This was a flash shot that was underexposed and brought back in post processing.

That works, just don't forget to also add some contrast in post to keep your shots from looking washed out.

[Canada_Rockies]

There is more "wiggle room" with RAW. Even my lowly K10D has 12 bit colour (4,096 shades per colour channel) as opposed to 8 bit colour (JPEG - 256 shades per colour channel). If you need pictures available for your friends in a hurry, use RAW+ and give them the JPEGs. The K-3, of course can save JPEG to one card and RAW to the other, but most of us only have one card slot.

[sterretje]

You can try the formula in this post by m42man for zoom lenses: https://www.pentaxforums.com/forums/6-pentax-dslr-discussion/142638-manual-fo...ml#post2256550