Do you need a Flattener for Micro Four Thirds

[wornish]

I have just got a Esprit 100 ED plus the flattener and the 48mm - Nikon adapter to use with my Nikon full frame camera as prime focus.

I would also like to use a Micro Four Thirds Camera but there does not seem to be any 48mm - M4/3 adapters out there to give the required 63mm spacing.

Because the M4/3 sensor size is quite a bit smaller is a flattener necessary ?  

 

 

[The Admiral]

Just a thought, but would you need a 48mm adapter? I should have thought a standard M42 thread of the T adapter would not give significant vignetting. I use a T adapter with my APS on a 102mm f/7 scope without a problem. Might give you more options.

Ian

[wornish]

18 hours ago, The Admiral said:

Just a thought, but would you need a 48mm adapter? I should have thought a standard M42 thread of the T adapter would not give significant vignetting. I use a T adapter with my APS on a 102mm f/7 scope without a problem. Might give you more options.

Ian

I haven't tested it yet (Clouds) but yes I know I can use a Standard Micro Four Thirds  T-adapter and get focus through a diagonal without the flattener installed.  

I am trying to find out in advance if a flattener is needed for a Micro Four Thirds camera or is the star field flat enough without one.  If I install the Skywatcher flattener then it only works if the sensor is exactly 63mm from the flattener.  So for full frame cameras you can get a specific adapters that screw into the flattener and attach direct to the camera lens mount so that this 63 mm is achieved.  The standard T-adapter is too big and places the camera too far away too have any effect.

I guess I am in unknown territory here seems that not many people are using micro four thirds cameras for imaging on a scope so will have to give it a try and see if its an issue, the reason I am trying this is because the micro four thirds cameras are much lighter, smaller and easier to control with free software than a full frame.

I have spoken to FLO who said they are not aware of any 48mm adapters for micro four thirds but they have pointed me to someone who makes custom adapters.

 

[The Admiral]

I know what you are saying Dave, but I thought that rather than worry about field flatness without your flattener, that you could use it with the flattener (and not through the diagonal) provided you opt for a T2 adapter for your camera. The standard for T2 is that the flange to film/sensor distance is 55mm, which is less than your 63mm, so it should be possible to get an M48-T2 adapter and use a T2 adapter for MFT. Low profile M48-T2 adapters are available from 365 Astronomy and Teleskop-Express; the one from FLO I think is a bit too deep. I have a Fuji X-T1, again a camera not commonly use in astrophotography, and which is mirrorless like yours, so in fact there is space to be had since the flange to sensor distance is not great. I got SRP-Photographic to manufacture a 'short' Fuji-T2 adapter for a reasonable sum (you'd need to email them as this service doesn't appear on their website now), and although I don't use it this way, it would probably provide sufficient space for an M42 adjustable extension so that you could 'tune' the spacing.

Just my two pennyworth.

Ian

[wornish]

Thanks for the input but it still doesn't work.  The flattener itself has a M65 thread.

 

The magic number for the flattener to sensor distance is 63mm.  so comparing the two makes of camera.

--------------------------------------------------Nikon F ------------------Micro 4/3

Flange to Focus distance ---------------------46.5 ----------------------19.25

Camera to M48 adapter------------------------ 8.5 --------------------Not Available

Camera to T2 adapter-------------------------- xxx---------------------- 35.75

T2 to M48 adapter -------------------------------------------------------- 8.0  

Flattener M65 - M48 spacer--------------------8.0------------------------ 8.0

                                                                                                             

Total Distance----------------------------------63.0 ---------------------- * 71.0  * too far.

 

So to work directly with the flattener I need one of three options 

a. - a micro 4/3 camera to M48 adapter thats 35.75mm wide  - don't exist

b. - a low profile T2 to Micro 4/3 adapter thats only 27.5 mm wide  - can't find one

c - a M65 to T2 adapter thats 8 mm wide - can't find one

Looks like custom job for option C.

 

[The Admiral]

10 hours ago, wornish said:

Thanks for the input but it still doesn't work.  The flattener itself has a M65 thread.

Ah, I hadn't realised that, I'd assumed it was M48. But presumably you have an adapter for the Nikon, so couldn't you use your Olympus with a MFT-Nikon mount converter in place of the Nikon? Wouldn't that put the MFT sensor in the same position as the Nikon's?

Ian

[wornish]

4 hours ago, The Admiral said:

Ah, I hadn't realised that, I'd assumed it was M48. But presumably you have an adapter for the Nikon, so couldn't you use your Olympus with a MFT-Nikon mount converter in place of the Nikon? Wouldn't that put the MFT sensor in the same position as the Nikon's?

Ian

Yes I do have the nikon to M4/3 mount converter as I sometimes  use my Nikon zoom lens on the m 4/3 camera. I have just measured it and its 27.15 flange to flange.

So :

Flange to Focus ---  19.25

M4/3 to Nikon F  -- 27.15  ( its a cheap one)

Nikon F to M48  ---  8.5

M48 to M65 --------  8.0

____________________

Total                    62.9   !!!!!!!!!!!!!

 

Thats pretty close you might have cracked it-  THANKS !

Now I need the clouds to go away and give it a try.