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02-18-2007, 08:44 PM   #1
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using k mount lenses on DSLR: worthwhile?

hey everyone, im new to photography and am interested in buying a DSLR camera. Recently iv inherited some old school camera gear off my now blind grandfather including :
-pentax k1000 asahi camera
-SMC pentax-m 1:2 50mm lens
-makinon 1:4.5 f=75-250mm lens
-2x teleconverter

I think that both lenses and the teleconverted are k-mounted. Im interested in buying a k100d for my first dslr because i figured it would be handy to be able to use the lenses i already have (particularly the 75-250mm).

However I read on the pentax website that k mounted lens are usable with some limitations on the k100d. Further research revieled that the lenses are only useful at full apeture. i know what this means, but i dont understand the its repercusions. how will that effect my photos? will it mean that the lens will only be usefull under certain lighting conditions? is it worthwhile to choose pentax over another brand just to be able to use k mounted lens, even though the lenses need to be at full apeture (aparently)?

any help would be really appreciated
thanks
Matt

02-18-2007, 08:51 PM   #2
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from my experience, the manual lenses i have work like the the autofocus lenses, provided i have my camera set to where you can use the aperature ring, but you dont get much information thnat you would get with the autofocus lens. and you have to focus manually all the time. you dont get the exposure level.
02-18-2007, 08:52 PM   #3
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Welcome to the forums, sgtfretsurfer!

I just posted some directions for one of the newer members here.

https://www.pentaxforums.com/forums/pentax-dslr-discussion/3020-using-k-lens-ds-2.html

I'm still learning to use my old manual lenses with a flash. Otherwise, it's been great fun. If you are not familiar with M mode, don't be afraid to kick it around, and post questions here. A lot of people will help out when they can.

Cheers!

P.S. Those two lenses are perfect to learn M mode!
02-18-2007, 08:55 PM   #4
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QuoteOriginally posted by shadowrulz3164 Quote
from my experience, the manual lenses i have work like the the autofocus lenses, provided i have my camera set to where you can use the aperature ring, but you dont get much information thnat you would get with the autofocus lens. and you have to focus manually all the time. you dont get the exposure level.
If you change your Preview mode to viewfinder, you will get your meter in M while turning the power switch to preview. I forget how to do this, but it's in custom. Will edit this post momentarily.

Edit:

Menu > Custom > Preview Method > Optical Preview.

Now when you twist the power switch to "Preview" hold it and look through. You will see the lens has stopped down to your aperture. Exposure meter to the very right, reading +3 through to -3, 0 is proper exposure. Shutter speed will flash if underexposed beyond 3 stops. Meter will flash if overexposed beyond 3 stops.

Cheers!


Last edited by Alvin; 02-18-2007 at 09:01 PM.
02-18-2007, 09:15 PM   #5
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Sgtfretsurfer...

I forgot to address the limitations you would be concerned about.

You can use your aperture ring on the K100D as I mentioned in my earlier post above. When you are focusing, like other cameras (including your K100) you are using the focus wide open. The camera will stop down depending on your aperture setting and you can preview it using the method above.

When using old lenses like the two you've got, you have only two metering modes available: Centre-weighted (default) and Spot. Most newer lenses (such as the kit 18-55mm and others) will allow a third mode (Matrix or Evaluative).

I hear from others that you can only use these lenses in Av or M mode. I haven't gotten my lenses working in any mode other than M.

With the K100D, your on board flash will fire at full power. You will have to fool around with the ISO, aperture, and shutter speed to try to obtain the best benefit of that flash. Maximum speed of the flash is 1/180th of a second.

Hope this all helps.
02-18-2007, 10:45 PM   #6
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You'll be able to use the full range of apertures. The only thing is that you have to fiddle with a couple of settings on the camera (which don't interfere with the use of "modern" lenses at all, so don't worry about that) and you'll have to manually meter the exposure.

The process is well outlined in other posts, so I'll just say that while it the explanation may look/sound confusing, in practice it is simplicity itself. It basically boils down to you selecting the aperture on the lens and then pushing the AE-L button to meter the scene and have the camera automatically set the shutter speed for you.

Naturally, that's not something you would want to be doing while trying to do something like shoot rapidly changing scenes like sports, but for other things the extra step is not burdensome at all and it lets you take advantage of using some lenses which may have a few years on them, yet which still take fantastic photographs.

Best of all, this ability to use practically any lens ever made for Pentax gives you a very broad range of choices for expanding your lens assortment by dipping into the deep pool of pre-loved lenses. It is a way to get quality lenses without paying the premium prices for new ones. It's a budget-challenged photographer's dream come true.

Many of those older lenses are still highly sought after today and command premium prices. At the same time, a great number of lenses which are in lower demand yet which can still provide quality results are widely available at very affordable prices.

The 50mm f2 lens you received is one of those. They sell for around $30-40 typically and can readily be found. The f1.4 and f1.7 versions of the 50mm lens are more highly prized, helping to keep the price of the less-loved f2 very affordable. I bought the "A" version of the 50mm/f2 lens from KEH for around $50 and love it. (Although just today I did pick up an "M" 50mm/f1.4 from eBay). Once you get the hang of the very easily learned manual metering process, you'll find that your 50/2 will provide you with many very satisfactory photographs. I have hanging on the wall next to me an A4 sized head shot of my son, taken with the 50/2. I couldn't be more pleased with it if I had gone to a studio and paid a professional to take it.

While the "M" lenses are perfectly useable, you will find that "A" lenses, with their ability to communicate aperture information to the camera, provide wider functionality and ease of use. For one thing, they're painless to use with Pentax's P-TTL flash, relieving you of the mental calisthenics of doing calculations with the flash's guide number and subject distance in order to figure out your aperture setting. You can choose from a range of apertures and the flash output will automatically adjust accordingly. Also, in aperture priority mode if you set the aperture ring to "A" the camera already "knows" what aperture you want to use and can automatically adjust exposure with normal metering, meaning you don't have to use the additional step of pressing the AE-L button. That means you can use it for rapidly changing scenes such as sports, provided you are handy enough with the manual focus. And with the ring set to "A" you can also use the "P" mode on the camera, which will automatically select both shutter speed and aperture for you, leaving you nothing to do manually but focus. Naturally, this greatly enhanced useability means that "A" lenses command higher prices than "M" lenses as a general thing. In my opinion, it is worth it, at least in lenses of a focal length which you foresee yourself using with flash.

To sum it up:

The ability to use these older lenses is one of the most endearing features of the Pentax dSLRs. They provide you the ability to get more bang for your buck, as well as an alternate stimulating and refreshing "mode" of enjoying photography. Their acquisition is relatively economical, the quality of photos is from good to excellent, and their use is not at all difficult to learn.

Come on in; the water's fine.
02-20-2007, 08:48 AM   #7
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QuoteOriginally posted by Alvin Quote
If you change your Preview mode to viewfinder, you will get your meter in M while turning the power switch to preview. I forget how to do this, but it's in custom. Will edit this post momentarily.

Edit:

Menu > Custom > Preview Method > Optical Preview.

Now when you twist the power switch to "Preview" hold it and look through. You will see the lens has stopped down to your aperture. Exposure meter to the very right, reading +3 through to -3, 0 is proper exposure. Shutter speed will flash if underexposed beyond 3 stops. Meter will flash if overexposed beyond 3 stops.

Cheers!
Cool stuff! I learn something every day.
02-20-2007, 11:10 AM   #8
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QuoteOriginally posted by rfortson Quote
Cool stuff! I learn something every day.
Glad to help

Oh did I mention, you can still adjust the aperture while you are previewing? I think you can do the same for the shutter speed too, but I haven't tried yet.

02-20-2007, 11:28 AM   #9
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Hi Matt
Welcome to the forum. I'll just reiterate what everyone else has said. You can get full use out of your old manual lenses, aperature ring and all. I recently acquired an SMC Pentax 50mm 1:1.2 lens. Over the last several weeks I've put it thru it's paces, shooting both indoors and outdoors. If you want to take a look at what you can do with a totally manual lens, check out this gallery for indoor shots:SmugMug - saltwater : K 50 1.2 lens test/Orchid Show
and this one for outdoor shots:SmugMug - saltwater : Perspectives
I'll be adding more outdoor shots probably this weekend, it's been rather chilly lately. In any event you can see that I've used a bunch of different apertures, you are not limited to wide open shots.

NaCl(hope that helps)H2O
02-20-2007, 03:03 PM   #10
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K mount and old lens

This is the reason I bought the K100 D, Pentax was my first lsr back the in dinosaur days. I have and Carl Ziliss Jena 2/58, Jena s 1:4 f=125 and a Asahi Pentax 42-5.6 300MM. Once I could the K mount adaputer it was almost like using my old camera all over again. Now all I have to do is post some of my shots. Go to it and start shoting ron
02-20-2007, 07:13 PM   #11
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K manual lenses with K100D

You mean I could be using an automatic lens with my K100D? Oh yes, it did come with one.

I bought my wife an ist-D when they first came out and myself a K100D in December mainly because we have over a dozen manual lenses from our K1000 Days. The only autofocus we have is my new 18-55 mm. It took awhile for us to find the option on the ist-D to allow manual control of the aperture, once selected my wife was a happy camper. She uses a Pentax macro often, the only expensive lens we have ($300 used) and she has avoided autofocus on her film SLRs for many years.

Both DSLRs work fine on full manual when you have the time to do it yourself. We don't do much that doesn't require a tripod. I confess, when I'm in a hurry I use a Fuji S5200 in full automatic or put the auto-focus lens on the K100D.

Leo Taylor
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