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12-04-2010, 09:43 AM   #1
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k-x w/ Quantaray LD 70-300mm auto apeture issue? help!

Greetings,
I'm new to both this forum and to dslr photography in general I'm hoping you will forgive the noob question but I'm struggling badly with this lens, any insight would be appreciated. issue is:

Bought a refurbished quantaray LD AF 70-300mm f/4-5.6 telemacro (shown in 3rd party zoom reviews here). when mounted to my K-x, the lens sent no data to the camera.

Couldn't trigger shutter even when aperture ring was set to A. so I cleaned contacts (didn't help) and set aperture other than A to allowed. Now with the ring set to A the AF operates and data is sent to the body but I cant seem to control the aperture from the camera.

In Manual or Av mode the apeture on the display screen is wide open at f/4 no matter how I adjust it, but (oddly?) the viewfinder displays the change in apeture as I move the thumb wheel. If I take my finger off the trigger for a few seconds the display screen shows the apeture I've selected . but when I half-press the trigger again to set up my shot it reverts back to F/4 on screen (but not in the viewfinder).

In livewiew the apeture reads blank F __ (this is still with the ring set to A and the apeture in the viewfinder set to f/22).

All my test shots exif data show f/4 no matter what I set the apeture to, and show a blank for lens type (q-ray is a re-badged tamron no?)

So, Is this a "noob" thing? a "3rd party lens compatibility" thing (im up a creek)? or a "I should send back to the refurbisher for repair" thing?

bought this as a learning lens for wildlife photos and also some nature macro. I can always learn to shoot with manual apeture or shoot stuck wide open, however I picked this lens over other crisper manual telephotos because of auto apeture flexability (that im currently not getting) that, and I got it for a song...

any advice, besides "be more brief" very appreciated.

12-04-2010, 08:31 PM   #2
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QuoteOriginally posted by seraph9 Quote
Greetings,
I'm new to both this forum and to dslr photography in general I'm hoping you will forgive the noob question but I'm struggling badly with this lens, any insight would be appreciated. issue is:

Bought a refurbished quantaray LD AF 70-300mm f/4-5.6 telemacro (shown in 3rd party zoom reviews here). when mounted to my K-x, the lens sent no data to the camera.

Couldn't trigger shutter even when aperture ring was set to A. so I cleaned contacts (didn't help) and set aperture other than A to allowed. Now with the ring set to A the AF operates and data is sent to the body but I cant seem to control the aperture from the camera.

In Manual or Av mode the apeture on the display screen is wide open at f/4 no matter how I adjust it, but (oddly?) the viewfinder displays the change in apeture as I move the thumb wheel. If I take my finger off the trigger for a few seconds the display screen shows the apeture I've selected . but when I half-press the trigger again to set up my shot it reverts back to F/4 on screen (but not in the viewfinder).

In livewiew the apeture reads blank F __ (this is still with the ring set to A and the apeture in the viewfinder set to f/22).

All my test shots exif data show f/4 no matter what I set the apeture to, and show a blank for lens type (q-ray is a re-badged tamron no?)

So, Is this a "noob" thing? a "3rd party lens compatibility" thing (im up a creek)? or a "I should send back to the refurbisher for repair" thing?

bought this as a learning lens for wildlife photos and also some nature macro. I can always learn to shoot with manual apeture or shoot stuck wide open, however I picked this lens over other crisper manual telephotos because of auto apeture flexability (that im currently not getting) that, and I got it for a song...

any advice, besides "be more brief" very appreciated.
2 things..

1. Somewhere in your custom menu, is an option that say Allow Aperture Ring. Set it to Permitted.

2. One of the contacts on the rear of the lens (one of the center ones) should extend/retract when you change from the A setting to any other setting on the lens. Make sure it is doing so. If it doesn't (reliably) there is your problem and you camera thinks this is a Non A type lens. In which case, see #1 for the reason your camera will not take a photo with the lens (when you are seeing the F--).

As to why it defaults to f4, I don't know. Probably the mode you are using, especially if you are using one of the full auto modes (scene modes). I didn't check the manual to refresh my memory on how the K-x works so someone else can jump in here if I'm wrong.

12-05-2010, 04:20 PM   #3
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Thanks for the input.

There does not seem to be a pin that extends when the ring is locked in A should there be one for a KaF mount? Theres a metal tab that shifts along a semicurcular slot as the ring is rotated through the manual apertures... there looks like theres no change in its position when you move the ring over from F/32 to A as it has nowhere to go... should it extend?

I guess I rambled on too much and wasn't particularly clear:

Allow aperture ring is set to "Permitted", ring is set to A.

The aperture is defaulting to wide open at f/4 no matter what mode the camera is set to (Ive tried all the priority modes all the scene modes, M, P, Auto. you name it)

In M the viewfinder will show whatever aperture I set with thumbwheel (screen still shows f/4 and that is all it will record at when the trigger is pressed, no matter what the viewfinder says) In Av the aperture changing in the viewfinder will alter the shutter speed to compensate but when the trigger is pressed I still get wide open with a now totally wrong shutter speed.

Wierder yet, when I switch autofocus off (in M or Av) the aperture box on info screen will blink rapidly back and forth between F/4 and whatever aperture I've set with the thumbwheel. Still records wide open no matter what.

I'm starting to suspect its a fault with the rom in the lens being unable to send info to the body with the ring set to A or something, Im just hoping its correctable. Anyone out there using this as a learning-lens on a K-x successfully?
12-05-2010, 04:51 PM   #4
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I have a Tokina 28mm prime that acts in a similar way... It has been 'shelved'...

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