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M adapter for T


Guest satrycon
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Guest satrycon

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i use a summilux 50 asph and summicron 90 apo asph on my T, with the M adapter.

 

whenever i switch lenses,after powering off; if i simply remove the lens from the the adapter [leaving the adapter on the body] and attach the other lens, after shooting i get "unknown lens" in the DNG/jpg EXIF data..

However, if i remove the M adapter as well and then swap lenses, everything's fine in the EXIF..

 

so is the body is reading some data from the M adapter even when powered off ?

 

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Tricky situations... let me recap the two kinds of actions... because if there is a power off within, your problem has probably to do with some information that is kept stored in Camera's memory during the power off phase. 

 

A )

1) Take a pic with (say) the 50  (it will be recorded with right lens in the exif)

2) power off the camera

3) remove the lens only and mount the 90

4) power on the camera

5) Take a pic : in the exif you have "unknown lens") 

 

Can be the camera stores in non volatile memory (permanently ? For "some time" only ?) the "last configuration mounted" (M adapter + 50)... when re-powered on and activated, it detectes an inconsistency of data that firmware isn't able to manage ("M adapter still on but 6 bit code not the same")  and this results in the "unknown lens" info.

 

B ) 

1) Take a pic with (say) the 50  (it will be recorded with right lens in the exif)

2) power off the camera

3) remove the M adapter, with the 50 on

4) Dismount the 50 / mount the 90 onto the adapter.

5) Power on the camera

6) Mount adapter + lens on the camera

7) Take a pic : 90mm lens is recorded  right  in the exif

 

not sure from your post if the above sequence is as I wrote...if it is like this, there is a different "reasoning" when camera is re-powered ("M Mount no more on" - after some seconds - "M Mount recognized" - "Let's check the lens" - "it's a 90"--> OK) 

 

On the contrary, if my  B )  process is not exactly the one you spoke about (i.e., 6) is performed BEFORE 5) , the "reasoning" of the camera ought not to be different from A) and I cannot explain the difference...

 

Anyway, as a person with longtime history in the Software world... one more evidence that software is really Tricky (and can be refined ad infinitum) in lot of situations....

Edited by luigi bertolotti
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Guest satrycon

scenario "A" is 100% correct..that's what happens.

 

For scenario "B", i have not tried mounting the adapter with lens attached while the camera is powered On.

 

 

it feels like as you say, some kind of non volatile memory of the last mounted lens...interesting

 

 

Tricky situations... let me recap the two kinds of actions... because if there is a power off within, your problem has probably to do with some information that is kept stored in Camera's memory during the power off phase. 

 

A )

1) Take a pic with (say) the 50  (it will be recorded with right lens in the exif)

2) power off the camera

3) remove the lens only and mount the 90

4) power on the camera

5) Take a pic : in the exif you have "unknown lens") 

 

Can be the camera stores in non volatile memory (permanently ? For "some time" only ?) the "last configuration mounted" (M adapter + 50)... when re-powered on and activated, it detectes an inconsistency of data that firmware isn't able to manage ("M adapter still on but 6 bit code not the same")  and this results in the "unknown lens" info.

 

B ) 

1) Take a pic with (say) the 50  (it will be recorded with right lens in the exif)

2) power off the camera

3) remove the M adapter, with the 50 on

4) Dismount the 50 / mount the 90 onto the adapter.

5) Power on the camera

6) Mount adapter + lens on the camera

7) Take a pic : 90mm lens is recorded  right  in the exif

 

not sure from your post if the above sequence is as I wrote...if it is like this, there is a different "reasoning" when camera is re-powered ("M Mount no more on" - after some seconds - "M Mount recognized" - "Let's check the lens" - "it's a 90"--> OK) 

 

On the contrary, if my  B )  process is not exactly the one you spoke about (i.e., 6) is performed BEFORE 5) , the "reasoning" of the camera ought not to be different from A) and I cannot explain the difference...

 

Anyway, as a person with longtime history in the Software world... one more evidence that software is really Tricky (and can be refined ad infinitum) in lot of situations....

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