K-Mount Treasures

Copyright © 2008 K-Mount Treasures Why do I need to use manual focus lenses on my modern DSLR? No, you don’t have to. But that is part of the fun of buying into Pentax K-Mount system. You can still use the old lenses made during the film days on the latest and greatest Pentax and Samsung DSLRs and you can get some beautiful pictures with them. You might already have some of these old Pentax lenses in your closet or you might know of a relative who might have some stashed away in their basement. Or better yet, you can get these lenses at bargain prices from eBay, pawn shops or local garage sale. Some of the Pentax primes made during the film days are of wonderful designs that can still take sharp pictures on your Pentax or Samsung DSLR. For more information read the article ‘10 Tips to get the most out of your new PENTAX DSLR’. What are K and M type lenses? The K and M type lenses do not know how to communicate aperture information to the camera. In old days, you had to select the aperture on your lens and you had to set the exposure on your camera manually by using match needle type of visual confirmation. It’s actually much easier to use the K and M type of lenses on your Pentax or Samsung DSLR. How are K and M type lenses different from A type lenses? The A type lenses are designed such that the camera can communicate with the lens on its aperture information mechanically. They have extra features that allow you to set both aperture and shutter speed in your camera without having to change anything on the lens. This is possible when the lens is set to the special ‘A’ setting and the camera is set to the Automatic or ‘A’ setting at the same time.
Getting started: configuring the camera Your Pentax or Samsung DSLR camera won't allow you to take pictures with K and M type Pentax lenses until you configure it properly. Here is the first step. Press the "Menu" button on the back of the camera body, use the right button (on the 4-way button or rocker set) and go right until you see the "Custom Setting" menu, and then go down a few menu pages until you see the "Using aperture ring" setting. Go right again, select "Permitted", and hit the OK button. Now you can use your K and M type manual lenses. Note that this only has to be done once, and there is no need to change the setting back again in order to use the auto-aperture or auto-focus lenses. Once you've set it, just leave it that way and your camera will happily work with whatever manual focus lens you throw at it.
Getting ready to shoot: mounting a manual lens The first step is to mount a K or M type manual focus lens on your DSLR camera. There is nothing special here for lenses designed for Pentax P/K bayonet mount - they mount just like autofocus ones. Screw-mount lenses or M42 lenses will work as well, except they need a M42-to-bayonet mount adapter. Read the article ‘10 Tips to get the most out of your new PENTAX DSLR’ for more information.
The second step is to set the dial on the top of the camera to the "M" (Manual) mode.
Next, set the focusing slider switch on the front of the camera to "MF" (Manual Focus). There are some options regarding focusing that we will mention below, but to get started "MF" will work best.
Turn on SR (Shake Reduction) by flipping the switch near the lower-right corner of the LCD.
...and then turn on the camera.
When the camera is powered up with Shake Reduction (SR) turned on and a manual lens mounted, it will ask you for the focal length of the lens. This is because there is no electronic communication between the camera and the manual lens. The camera has no way to know what lens it is mated with. It was very thoughtful of Pentax to allow manual input of the focal length for legacy lenses so that the camera can still apply the right amount of SR to compensate for the vibration in the sensor for a given lens. Use the left/right directional keys on the back of the camera to select the proper focal length and press OK. If you are using a zoom then try to choose a focal length that is as close to what you'll actually shoot with as possible. For example, if you are planning to use a M 80-200mm zoom lens at around the halfway point, choose 135mm as the focal length. If you are using one of those fantastic legacy 50mm Pentax primes, this is what you are going to see at this point. Note: You will not see this screen if you turn on SR with the camera already powered up. You can get to this screen by going through the menu screens (it's just about the last item on the "record" menu), but you will find it quicker just to turn the camera off and then on again. And now you're ready to shoot some beautiful photographs with that K or M type manual lens!
Shooting It will take longer to describe this than it does to actually take a shot, so bear with us. First, set the aperture ring on the lens to the f/stop you will use:
Next, look through the viewfinder and focus:
Half-press the shutter button to turn on the exposure meter.
You can tell that the meter is on when the green hexagonal focus confirmation light below the viewfinder image lights up. Because it's a manual lens, the camera has no idea what f/number you've set it to, so it will show "F (blank)" for the aperture. Note: there's a menu option that controls how long the meter stays on. Use it if the focus confirmation light shuts off too quickly for your taste. And here's the secret to metering with the K and M type manual lenses: While the meter is still on, press the "AE-L" button on the back of the camera for Pentax *ist DS, DS2, DL, DL2, K100D, K110D or the Samsung GX-1S, GX-1L (very close to where you thumb naturally sits) green button for Pentax *ist D, K200D, K10D, K20D or Samsung GX-10, GX-20 (next to the top LCD panel)
	When you hit this button the camera will momentarily stop down the lens (or close the aperture blades) to take a light reading, then it will set the proper shutter speed to the programmed exposure. At this point you will most likely find the viewfinder to darken a bit. You'll see the new shutter speed in the green digits below the viewfinder image. After setting the shutter speed the camera will immediately open back the lens aperture again and the viewfinder will be bright again. This whole thing takes about a second.
If you think the shutter speed is too slow for hand holding (or too fast!), adjust the aperture (or ISO sensitivity) and repeat the steps: Press the shutter button half-way to turn on the meter and then Press the AE-L button or the green button to set the shutter speed.
Everything is set! Now just fully depress the shutter button to take the picture. Check your LCD for sharpness and histogram to make sure you have the correct exposure to your liking.             ...and that's it! Once you've got the aperture set in the range you want, the only difference between shooting an automatic vs. a K or M type manual lens is that you have to focus the latter manually (duh!) and you have to press the AE-L or green button to set the shutter speed. And if the lighting conditions aren't changing, then you don't even have to do that. In fact, with constant lighting and a subject that stays within your depth of field, you can probably fire shots off even faster than with an automatic lens! Keep this in mind when you are shooting macro or a still subject.
More on focusing One of the interesting things that your DSLR camera can do is to "assist" your manual focusing. This is enabled in the custom setup menu ("FI with S lens used"). If this is enabled, the autofocus sensor monitors your focusing (using the center focus point only) while the meter is on. When you hit the right focus point the green hexagonal focus confirmation light below the viewfinder will light up (you will hear a beep as well) and stay on. People have found that in dim lighting conditions and with fast lenses such as 50mm f/1.4, the focus detection is very touchy and seems more distracting than helpful. Most times it helps to just trust your own eyes to make sure that what you see through the viewfinder is clear enough for you before you trip the shutter, rather than depend on the focus confirmation light and the beep to guide you. If you find it too annoying you can just go into the menu and disable it (“FI with S lens used”). If you do enable the focus assist, you can also use what is known as "focus trap" mode. This is enabled by turning the autofocus switch to the "AF" position. Of course the camera cannot actually autofocus a manual lens, but in this position it will disable the shutter button unless you have locked on to a good focus and the green hexagon is lit in the viewfinder and an audible beep is heard at the same time. You should be able to use this for difficult focusing situations such as for macro photography. Set the autofocus switch to "AF", frame the subject in the viewfinder, focus as best you can and then hold down the shutter button while sloooowwly moving to and from the subject using the manual focusing ring on the lens. With the shutter button held down, the camera will fire as soon as you hit the correct focus point. Summary There you have it! Now you can use those old classic Pentax K and M type legacy lenses on your modern Pentax/Samsung DSLRs. There are a few things that need to be set up, but once done it is actually very easy and fun. Chances are you will get addicted to using those manual focus lenses. Pressing the AE-L or the green button to set the shutter speed is much simpler and faster than mucking with the shutter speed dial on an old classic film camera like the K1000 or the ME Super (if you ever had the pleasure of using them). Keep in mind that the smaller APS-C sensor used in Pentax and Samsung DSLRs means that lenses have a reduced field of view compared to when they are used on a full-frame 35mm camera. The effect is like multiplying their focal length by 1.5, so that a 50mm lens on a DSLR gives you the same picture you would get with a 75mm lens on a film camera. This is a disadvantage if you want to take wide angle shots, but an advantage for telephoto. If you have got some good old K and M type Pentax lenses lying around, your new Pentax or Samsung DSLRs will put them to good use. With Pentax K-Mount, old is gold!