Reading mode: Light Dark

Setting the focal length when the 'exotic' lens is not detected

Go to last post
D

DavidWright2010

Senior Member
Messages
4,669
Solutions
7
Reaction score
4,516
Location
Northern, CA, US
I couldn't find any info on this question with a search, so maybe an expert here can help me.

When I use a manual (Rokinon) lens on my K-70, the cam recognizes there is a lens and prompts me for a FL.

However, when I attach something more exotic , nothing is recognized, and the FL in the cam (and in the EXIF) is 0.0. Normally I wouldn't care about that, but astrotracer does not work with that OTA. I can take a picture with the Rokinon and astrotracer mode, and the stars are points (more or less) on a 10 sec exposure. With the Baker-Schmidt, the cam and exif record that I am operating in astrotracer mode, but there is no sensor shift going on. It's exactly the same result as when I use 'manual' mode.

I'm thinking that the astrotracer algorithm uses the FL, and when it is zero something bad happens.

But I don't see anywhere in the menu system (or the users manual) where I can enter a FL. How do I do this?

David
 
DavidWright2010 said:
I couldn't find any info on this question with a search, so maybe an expert here can help me.

When I use a manual (Rokinon) lens on my K-70, the cam recognizes there is a lens and prompts me for a FL.

However, when I attach something more exotic , nothing is recognized, and the FL in the cam (and in the EXIF) is 0.0. Normally I wouldn't care about that, but astrotracer does not work with that OTA. I can take a picture with the Rokinon and astrotracer mode, and the stars are points (more or less) on a 10 sec exposure. With the Baker-Schmidt, the cam and exif record that I am operating in astrotracer mode, but there is no sensor shift going on. It's exactly the same result as when I use 'manual' mode.

I'm thinking that the astrotracer algorithm uses the FL, and when it is zero something bad happens.

But I don't see anywhere in the menu system (or the users manual) where I can enter a FL. How do I do this?

David
Click to expand...
In the custom menu set "Use Aperture Ring" to "Permitted" or "Enabled" whatever term they chose for that model.

--
Mike from Canada
"I am not a great photographer! God is a great creator! All I do is capture His creation with the tools He has provided me."
'I like to think so far outside the box that it would require a telephoto lens just to see the box!' ~ 'My Quote :)'
http://www.michaelfastphotography.com/galleries/VP-BDI_3a.jpg
http://www.airliners.net/search/[email protected]&thumbnails=
 
Last edited:
MightyMike said:
DavidWright2010 said:
I couldn't find any info on this question with a search, so maybe an expert here can help me.

When I use a manual (Rokinon) lens on my K-70, the cam recognizes there is a lens and prompts me for a FL.

However, when I attach something more exotic , nothing is recognized, and the FL in the cam (and in the EXIF) is 0.0. Normally I wouldn't care about that, but astrotracer does not work with that OTA. I can take a picture with the Rokinon and astrotracer mode, and the stars are points (more or less) on a 10 sec exposure. With the Baker-Schmidt, the cam and exif record that I am operating in astrotracer mode, but there is no sensor shift going on. It's exactly the same result as when I use 'manual' mode.

I'm thinking that the astrotracer algorithm uses the FL, and when it is zero something bad happens.

But I don't see anywhere in the menu system (or the users manual) where I can enter a FL. How do I do this?

David
Click to expand...
In the custom menu set "Use Aperture Ring" to "Permitted" or "Enabled" whatever term they chose for that model.
Click to expand...
 
The camera detects that there is an ”old” lens attached when the electric contacts in the mount are short circuit by the metal of the lens mount. So clean the lenses mount from oxid or dirt. Also the camera doesn’t bother asking for a focal length unless the SR is set to on.
 
GimbalLock said:
The camera detects that there is an ”old” lens attached when the electric contacts in the mount are short circuit by the metal of the lens mount. So clean the lenses mount from oxid or dirt. Also the camera doesn’t bother asking for a focal length unless the SR is set to on.
Click to expand...
OK, so when I said that this is similar to using legacy lenses, I was wrong.

This is attaching a telescope t-adapter to the camera. Specifically it is the Bower t-mount to Pentax adapter - $12 from B&H. I guess it's metal, but with a non-conductive coating.

And it's only a guess on my part that lack of FL info is why astrotracer doesn't work.

David
 
GimbalLock said:
The camera detects that there is an ”old” lens attached when the electric contacts in the mount are short circuit by the metal of the lens mount. So clean the lenses mount from oxid or dirt. Also the camera doesn’t bother asking for a focal length unless the SR is set to on.
Click to expand...
Ok so I forgot about the input focal length option but I tested the K-1 and even with the lens off, no shorting it still asked for the focal length when i turned it on... Even with SR turned off it still asked for the focal length with nothing attached.
 
DavidWright2010 said:
GimbalLock said:
The camera detects that there is an ”old” lens attached when the electric contacts in the mount are short circuit by the metal of the lens mount. So clean the lenses mount from oxid or dirt. Also the camera doesn’t bother asking for a focal length unless the SR is set to on.
Click to expand...
OK, so when I said that this is similar to using legacy lenses, I was wrong.

This is attaching a telescope t-adapter to the camera. Specifically it is the Bower t-mount to Pentax adapter - $12 from B&H. I guess it's metal, but with a non-conductive coating.

And it's only a guess on my part that lack of FL info is why astrotracer doesn't work.

David
Click to expand...
Get a little aluminum foil and stick it between the t-mount and the camera mount, that will short the pins. Its a reasonable hypothesis that astrotracer needs the focal length
 
That or sand off the black paint in the area of the T-ring that matches the camera contacts. It what I have to do to use a telescope many times.
 
Mike, Kent-

I will try some Al foil and report back.

David
 
DavidWright2010 said:
Mike, Kent-

I will try some Al foil and report back.

David
Click to expand...
The foil did not cause the 'set focal length' screen to appear.

Next I will try updating the firmware to 1.11 (it's currently 1.0). Maybe that will allow the FL to be set even when there is no lens (as with the K-1).

David
 
DavidWright2010 said:
DavidWright2010 said:
Mike, Kent-

I will try some Al foil and report back.

David
Click to expand...
The foil did not cause the 'set focal length' screen to appear.

Next I will try updating the firmware to 1.11 (it's currently 1.0). Maybe that will allow the FL to be set even when there is no lens (as with the K-1).

David
Click to expand...
Does the camera ask you for a focal length when you turn it on with no lens on it?

--
Mike from Canada
"I am not a great photographer! God is a great creator! All I do is capture His creation with the tools He has provided me."
'I like to think so far outside the box that it would require a telephoto lens just to see the box!' ~ 'My Quote :)'
http://www.michaelfastphotography.com/galleries/VP-BDI_3a.jpg
http://www.airliners.net/search/[email protected]&thumbnails=
 
Last edited:
DavidWright2010 said:
MightyMike said:
DavidWright2010 said:
DavidWright2010 said:
Mike, Kent-

I will try some Al foil and report back.

David
Click to expand...
The foil did not cause the 'set focal length' screen to appear.

Next I will try updating the firmware to 1.11 (it's currently 1.0). Maybe that will allow the FL to be set even when there is no lens (as with the K-1).

David
Click to expand...
Does the camera ask you for a focal length when you turn it on with no lens on it?
Click to expand...
Click to expand...
 
MightyMike said:
DavidWright2010 said:
MightyMike said:
DavidWright2010 said:
DavidWright2010 said:
Mike, Kent-

I will try some Al foil and report back.

David
Click to expand...
The foil did not cause the 'set focal length' screen to appear.

Next I will try updating the firmware to 1.11 (it's currently 1.0). Maybe that will allow the FL to be set even when there is no lens (as with the K-1).

David
Click to expand...
Does the camera ask you for a focal length when you turn it on with no lens on it?
Click to expand...
Click to expand...
Click to expand...
 
DavidWright2010 said:
MightyMike said:
DavidWright2010 said:
MightyMike said:
DavidWright2010 said:
DavidWright2010 said:
Mike, Kent-

I will try some Al foil and report back.

David
Click to expand...
The foil did not cause the 'set focal length' screen to appear.

Next I will try updating the firmware to 1.11 (it's currently 1.0). Maybe that will allow the FL to be set even when there is no lens (as with the K-1).

David
Click to expand...
Does the camera ask you for a focal length when you turn it on with no lens on it?
Click to expand...
Click to expand...
Click to expand...
Click to expand...
 
MightyMike said:
I assume you're using the O-GPS thingy, I don't think they built astro tracer into the camera did they?

--
Mike from Canada
"I am not a great photographer! God is a great creator! All I do is capture His creation with the tools He has provided me."
'I like to think so far outside the box that it would require a telephoto lens just to see the box!' ~ 'My Quote :)'
http://www.michaelfastphotography.com/galleries/VP-BDI_3a.jpg
http://www.airliners.net/search/[email protected]&thumbnails=
Click to expand...
Right. The The O-GPS1.

Maybe I should rephrase my question as, "does anyone use the K-70 in astrotracer mode with a telescope".

David
 
Atindra said:
DavidWright2010 said:
MightyMike said:
DavidWright2010 said:
MightyMike said:
I assume you're using the O-GPS thingy, I don't think they built astro tracer into the camera did they?

--
Mike from Canada
"I am not a great photographer! God is a great creator! All I do is capture His creation with the tools He has provided me."
'I like to think so far outside the box that it would require a telephoto lens just to see the box!' ~ 'My Quote :)'
http://www.michaelfastphotography.com/galleries/VP-BDI_3a.jpg
http://www.airliners.net/search/[email protected]&thumbnails=
Click to expand...
Right. The The O-GPS1.

Maybe I should rephrase my question as, "does anyone use the K-70 in astrotracer mode with a telescope".

David
Click to expand...
No, rephrase the question... as in new post, asking how you set the focal length on the K-70 when no lens or a completely manual lens is attached.

--
Mike from Canada
"I am not a great photographer! God is a great creator! All I do is capture His creation with the tools He has provided me."
'I like to think so far outside the box that it would require a telephoto lens just to see the box!' ~ 'My Quote :)'
http://www.michaelfastphotography.com/galleries/VP-BDI_3a.jpg
http://www.airliners.net/search/[email protected]&thumbnails=
Click to expand...
I’ll do that. But that is making the assumption that astrotracer will work once the FL is set. A reasonable assumption, but not proven.
Click to expand...
Have a look at the manual of K-70 at Page 121 (including appendix and caution). I think there lies your answer. Apreture ring to be set to enable. Also read Page 123 too.

I was figuring to use Manual A* lens and could not register the focal length and F values were flashing like F-- on LCD and shutter press was disabled. I just read the details on above mentioned pages and I think it might solve what trouble I was facing and may be your solution too.

All the best

Atindra
Click to expand...
That is important to do if the manual lens has a aperture ring. In my case (telescope t-adapter), there is no aperture ring.
 
You must log in or register to reply here.

Keyboard shortcuts

f
Forum
m
My threads
Mobile site
About
Editorial content
Cameras & Lenses
Community
All content, design, and layout are Copyright © 1998–2025 Digital Photography Review All Rights Reserved.
Reproduction in whole or part in any form or medium without specific written permission is prohibited.
When you use DPReview links to buy products, the site may earn a commission.
©GPS Media - Guides, Products, Services.
Back
Top