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08-12-2009, 03:47 AM   #1
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Pentax K10d/ZX-7 stupid questions

I threw that right out in the title so no one can get mad at me. I have both of the cameras listed above. I also have a series of lenses, etc that I love. Here are my multitude of questions: I read that the K10d is a crippled KAF mount, which means it will accept any K, A, or F lens with certain limited capabilities (<~I'm really proud I understand that sentence). So, if I bought a bunch of lenses for my ZX-7 they are compatible with my k10d. Now, the question that then arises is this: I read that one of the limited capabilities in using a manual lens on a digital camera is that the auto focus will work but not as well as on the manual. So, having tried to use the A feature on my lenses in a small variety of lighting conditions, should I stop beating my head against a wall and give that up? The reason I ask is two fold: I have one 'digital' lens for the k10d, an 18-55. It has no A button or really anything that doesn't limit it to very little but point and shoot. I am trying to move beyond the whole point and shoot thing and get into Aperture and focal point, etc etc. I take good pictures, good enough to get accepted to an art program at my school, but I don't want to walk into the first day of photography classes in the spring semester feeling like a total twit.
Also, I have a macro lens by Quantaray which is quite easily my favorite lens. I have had issues lately with my friendly local camera shop not necessarily having the accessories I want. Besides KEH, can anyone name a good place online that I can buy filters, etc for a Quantaray 70-200 MM?
Lastly, given both the questions above, should I go ahead and set aside money to buy a bunch of new lenses? I can work with the ones I have now without too many issues, and would have to find something similar (I have issues with technology). I'm also a broke ass college student, and every lens I buy is one week without food (not really, but its tight). A little help?
P.S. I bolded my questions: I'm long winded at the best of times.

Last edited by agray24; 08-12-2009 at 03:48 AM. Reason: bolding questions
08-12-2009, 04:01 AM   #2
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I should say that I have read the article stickied at the top of this forum, and while it was helpful in certain respects, I don't see the answer I'm looking for.
Also, I think I might have phrased the first question wrong: Basically, the answer to the question is a yes or no. I am planning on using manual focus, etc etc eventually, but the article that I read on the limitations of manual lenses on dslr's mentioned that certain functions would not work, and I was wondering if the aperture ring was one of them.
08-12-2009, 04:55 AM   #3
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I am planning on using manual focus, etc etc eventually, but the article that I read on the limitations of manual lenses on dslr's mentioned that certain functions would not work, and I was wondering if the aperture ring was one of them.
The aperture ring will most certainly work on old screw mount, K, and M series lenses but you will have to set it manually. The green button works but I tend to rely more on the old "sunny sixteen" rule, the histogram and trial and error.


Tom G
08-12-2009, 07:22 AM   #4
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Manual lenses on K10D

First of all, the K10D can not auto-focus with a manual lens attached. The lens simply doesn't have the mechanism to allow the camera to drive the focus. What you may have heard is that the focus indicator will tell you when you have correctly focused the lens manually. In fact, if the camera is set to AF-S, it won't trip the shutter until you have achieved what the camera thinks is correct focus. If you don't like that, either set the camera to manual focus or AF-C, which will allow an out-of-focus shot.

The easiest lenses to use are the A-series lenses, which have the "A" setting on the aperture ring. In this case, the only thing you give up is auto-focus. Set the lens on "A", and use the camera controls to set the aperture. All exposure modes work with this setting.

If you have a lens without the "A" setting, such as a K, M-series or M42 screwmount lens (with adapter), you will have to find the option in the menus to "allow aperture ring". Without this set, the camera will just sit there and display "F--" on the top LCD.

The K10D, and all Pentax digital slrs, have a "crippled" k-mount, in that they lack the mechanism for the manual k-mount lenses to tell the camera what aperture they are set at. This means that you must use stop-down metering. A few of the last film cameras in the ZX/MZ series were this way, as well. I know that my ZX-60 is.

All that said, I like to use the Super Takumar 50mm, f/1.4 screwmount lens on my K10D. I simply set the lens in manual mode, the camera in Av mode, focus, twist the aperture ring until I get the f-stop I want, and fire away. The camera picks the shutter speed.

Note, also, that the SR won't know the focal length of the lens that is mounted. It will ask you for this info. Enter the actual focal length. Do not multiply by 1.5 to account for the "crop factor". The focal length of the lens doesn't change when you put it on a digital camera.

08-12-2009, 08:27 AM   #5
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There are no stupid questions, everybody starts at the beginning.

Your lenses are fine. The only difference between your ZX-7 and K10D lens-wise is that your ZX-7 can recognize when you change the aperture setting on the aperture ring. If you leave your lenses (that have aperture rings) set to 'A' at all times, they'll behave the same in this respect.

That 'A' position has nothing to do with manual focus. What it means is that the lens aperture is being controlled by the camera body. Think of the DA18-55 as only offering that 'A' position--it requires the body to control the aperture.

Even on your ZX-7, the body can control the aperture, so there's no need to use the aperture ring as long as it's set to the 'A' position. If the ZX-7 is set to 'Av', the lever that surrounds the shutter release controls aperture (right fingers). If it is set to 'M', it controls aperture while you have the little Av/+- button next to the lens held pressed down (left thumb). It is indirectly controlled when you're shooting in auto, program, or Tv modes.

The K10D normally controls the aperture with the rear e-dial (right thumb) when in Av, TAv, M, B, or X shooting modes, and when HyperProgram is invoked in P. Again, aperture ring on all lenses that offer it should be set to 'A'.

If there IS an aperture ring, and there is no 'A' position (that button only serves to 'lock' the ring into 'A' position), what you have is an older manual focus lens such as Pentax-M or the like. These will work as designed on your ZX-7, the difference being that you control aperture with that ring, and you're limited to Av (aperture priority) or manual shooting modes. No full auto with lenses like this. On your K10D, you generally need to shoot these with stop-down metering in M(anual) mode only. There's a sticky thread in this forum regarding use of the green button for doing this that you should read if this is what you're using.

As for focusing manual focus lenses, it'll just take a little practice. In both cases, put the camera in manual focus mode, and with the shutter button half-pressed, adjust focus until the little hexagon-shaped focus confirmation light illuminates. It uses the same central sensor (autofocus 'point') that the autofocus system uses, it's just that your brain is the 'AF logic' and your fingers are the 'motor'.

You can get filters anywhere. B&H and Adorama are good & reliable online & brick/mortar (in NYC) stores, though there's lots of good used stuff at KEH.

You might want to specifically identify your lenses as best you can for more specific help.
08-12-2009, 08:58 AM   #6
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The autofocus CAN work with manual lenses...!

Dear Agray24:

The PIPE here...and on a page here at specifically at , whre I relate my experiences that sum up my very first serious shooting session with my veteran Vivitar Series One 70-210mm all manual zoom telephoto lens on my digital Pentax K100D camera.

That lens of mine was purchased quite some time ago (the better part of twenty years ago!) from, and it certainly did NOT let me down on the K100D!

Setting the K100D up to use the Vivitar DID involve setting the camera to "allow aperture ring" inputs when I used the "AE-F" button function on the K100D...the exact equivalent of the "green button" on your get a good, usable aperture setting while in "M" manual mode on the K100D's function dial...

...and when that front-of-the-camera switch IS set to "AF" for autofocus, when using a MANUAL lens, the camera will ONLY let you take a photo, IF you're in focus, as AndrewG NY reminded us in this thread, when the "little green hexagon" at the bottom center of the viewfinder (where it exists on my K100D) is lit...I found that out while I was shooting the RC Scale model aircraft photos in my listed forum link, that were shot almost a year ago as I write this.

I'm STILL out of work (almost a year now) NO "new-to-me" lenses for the present. IF the Sigma 135-400 "Li'l Bigma" Pentax-mount AF zoom telephoto lens I spotted up at late last week for about $360 manages to stay there long enough, and I DO end up getting back to work in the next couple of months, I MIGHT get that, as my 1980-vintage "film burner" Pentax K1000SE can use it too...and there IS another potential good choice in the Sigma 70-300 APO DG zoom tele lens for a bit less money (even the new ones) if that 135-400 can't be found anywhere in the future.

Hope you can get used to trying the "AF" mode with your manual lenses, after setting your K10D up to "allow aperture ring" usage...just check your manual for an entry in its index about that above term about how to do it, and you'll be off and running with your manual lenses on your K10D... of luck!

Yours Sincerely,

08-12-2009, 06:43 PM   #7
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QuoteOriginally posted by agray24 Quote
The reason I ask is two fold: I have one 'digital' lens for the k10d, an 18-55. It has no A button or really anything that doesn't limit it to very little but point and shoot. I am trying to move beyond the whole point and shoot thing and get into Aperture and focal point, etc etc.
There is nothing P&S about a lens without an aperture dial. The aperture is simply mechanically controlled differently. The camera moves the aperture arm on the lens to set the aperture as apposed to the lens moving the arm. You have full control of how it is set depending on the mode you use your K10D in. Even then, you probably have more control than you think.

I would suggest that you put the film camera aside and start using your K10D in manual mode with the lenses you currently have. I wouldn't worry about manually focusing anything until you have simply mastered using aperture, shutter speed, and ISO.

Once you actually figure out how to use your K10D in manual mode, then switch to the automated modes and learn to really understand how they work. The point is not to get great photos or photos good enough to get you into art school, but to understand how the settings get you great photos, and how the modes make getting a great photo easier by adjusting one or two of the three settings. You should also understand how EV compensation works in each mode and what setting, of the three, is used to apply that compensation.

Thank you

Last edited by Russell-Evans; 08-13-2009 at 11:04 AM.

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