Help with new lens

Natalie Roy · 06-16-2010, 09:23 PM

Hi There All,

Any help would be greatly appreciated as I am very new to SLR photography! I have a K-x that I have been enjoying and just purchased a Pentax - F SMC 4.7-5.6 80-200mm lens. I put it on the camera and everything appears dark! Yikes! It's dark throught the view finder and dark through on the display monitor. Have I done something wrong? I can't find anything referencing this is the manual.....

Thanks in advance!

wshi · 06-16-2010, 09:37 PM

Don't take this the wrong way, but did you remove the lens cap?

KxBlaze · 06-16-2010, 09:43 PM

Is it completely dark or can you see an image that is very dark? If you can at least see an image than make sure the lens is 100% all the way on. If the lens didn't "click" all the way on then you will get a very dark image.

**kiwi_jono** · 06-16-2010, 09:55 PM

Another (perhaps obvious question):

Is the lense apperture ring set firmly to "A" position?

Just1MoreDave · 06-17-2010, 06:12 PM

Dark is subjective, so just so we're talking about the same thing, the viewfinder brightness should be similar to the DA-L 18-55mm lens that came with your camera when that lens is close to 55mm. They'll vary a little and can't be set to the same focal length, so you can't see exactly the same view, but shouldn't be dramatically different.

The lens has an aperture that opens and closes to let in different amounts of light. When it is correctly attached to the camera, that aperture is always fully opened. Your F80-200 has an aperture ring that can open and close this aperture manually. Normally, you should set the lens's aperture ring to its A position and leave it there. On the K-x, the lens will work better that way.

As suggested above, make sure the lens is correctly mounted until it locks. It should feel exactly like mounting your kit lens. If you mount the kit lens, you can see the aperture blades move from fully closed to fully open as the lens is rotated into locking position. That's what should be happening with the F80-200. The blades are a little deeper in the lens but you can see them.

If that doesn't help, the only thing I can think of is a mechanical problem with the aperture lever. That is the protruding part on the lens mount that allows the camera to move the aperture blades. It could be bent, so the camera's control arm doesn't make contact with it. Or the spring could be broken or missing. With the lens off the camera, you should be able to flick this spring-loaded lever and make the blades snap open, then spring closed. You can also turn the aperture ring from A to the opposite end (I think it says 4.7 on this lens) and the blades should open up also. The aperture lever should look a lot like the one on your kit lens, sticking straight back.

06-16-2010, 09:23 PM	#1
Natalie Roy New Member Join Date: Jan 2010 Location: Lebanon, CT Posts: 1	Help with new lens Hi There All, Any help would be greatly appreciated as I am very new to SLR photography! I have a K-x that I have been enjoying and just purchased a Pentax - F SMC 4.7-5.6 80-200mm lens. I put it on the camera and everything appears dark! Yikes! It's dark throught the view finder and dark through on the display monitor. Have I done something wrong? I can't find anything referencing this is the manual..... Thanks in advance!

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06-16-2010, 09:37 PM	#2
wshi Veteran Member Join Date: Dec 2009 Location: Illinois Posts: 455	Don't take this the wrong way, but did you remove the lens cap?

06-16-2010, 09:43 PM	#3
KxBlaze Veteran Member Join Date: Feb 2010 Location: California Photos: Gallery Posts: 1,594	Is it completely dark or can you see an image that is very dark? If you can at least see an image than make sure the lens is 100% all the way on. If the lens didn't "click" all the way on then you will get a very dark image.

06-16-2010, 09:55 PM	#4
kiwi_jono Site Supporter Join Date: Dec 2009 Location: Christchurch, New Zealand Photos: Gallery \| Albums Posts: 1,083	Another (perhaps obvious question): Is the lense apperture ring set firmly to "A" position?

06-17-2010, 06:12 PM	#5
Just1MoreDave Pentaxian Join Date: Feb 2007 Location: Aurora, CO Photos: Gallery \| Albums Posts: 4,859	Dark is subjective, so just so we're talking about the same thing, the viewfinder brightness should be similar to the DA-L 18-55mm lens that came with your camera when that lens is close to 55mm. They'll vary a little and can't be set to the same focal length, so you can't see exactly the same view, but shouldn't be dramatically different. The lens has an aperture that opens and closes to let in different amounts of light. When it is correctly attached to the camera, that aperture is always fully opened. Your F80-200 has an aperture ring that can open and close this aperture manually. Normally, you should set the lens's aperture ring to its A position and leave it there. On the K-x, the lens will work better that way. As suggested above, make sure the lens is correctly mounted until it locks. It should feel exactly like mounting your kit lens. If you mount the kit lens, you can see the aperture blades move from fully closed to fully open as the lens is rotated into locking position. That's what should be happening with the F80-200. The blades are a little deeper in the lens but you can see them. If that doesn't help, the only thing I can think of is a mechanical problem with the aperture lever. That is the protruding part on the lens mount that allows the camera to move the aperture blades. It could be bent, so the camera's control arm doesn't make contact with it. Or the spring could be broken or missing. With the lens off the camera, you should be able to flick this spring-loaded lever and make the blades snap open, then spring closed. You can also turn the aperture ring from A to the opposite end (I think it says 4.7 on this lens) and the blades should open up also. The aperture lever should look a lot like the one on your kit lens, sticking straight back.