dark current noise

To any of you who have any of the larger Oly M43 bodies like the EM1,5, or 10, how does the EPL-6 handle dark noise at longer exposures at higher ISO compared to those cameras? It's still been mostly cloudy around here so I haven't been able to test it- but basically what I'm looking for is if the noise is fairly low up to ISO 3200 and 1 minute exposures for pictures of constellations like Orion? Is the noise level at those exposures comparable to the larger bodies? And does dark frame subtraction help remove a lot of it in camera?

I've seen some great images of Orion and other constellations taken at ISO 1600-3200 up to 1 minute exposures with the EM1, 5 and 10 and I was wondering if the smaller body of the EPL6 builds up noise more quickly at higher ISO and longer exposures like that or if it's about the same and if dark frame subtraction deals with it nicely.

The following is one of my favorite ones:

http://www.dpreview.com/forums/post/56950284

I own a EM5 and EM1.

Both can do great shots of night skies, but the EM1 really needs darkframe subtraction at 8 seonds and longer exposure.

EM1 versus EM5 dark current noise (with and without darkframe aka "NR")

EM5 is easier to handle regarding dark current but on the other hand it adds some magenta color cast to the hight iso/low light exposures. With darkframe and exposures at 30 seconds, I prefer the EM1. Without darkframe (star trails) and very long exposure I prefer the EM5.

I think the PL6 you mentioned is similar to my EM5 including the magenta color cast.

Would be interesting to know if ALL newer cameras with the current TruePic VII engine (EM1, EM10, EM5 II, EPL7) have better color cast handling. In this case a camera with Sony Sensor and TruePic VII engine (EM10, EPL7) would be the optimum.

Christof

alexisgreat wrote:

To any of you who have any of the larger Oly M43 bodies like the EM1,5, or 10, how does the EPL-6 handle dark noise at longer exposures at higher ISO compared to those cameras?

It's the same for all Olympus cameras with the 16mp Sony sensor. E-M1 is an exception, as it uses Panasonic sensor, and thus exhibits higher levels of dark current noise. See here , here and here for example. You can use google translate, but even looking at the table and histograms at the bottom of those should be enough. An E-PL5/6 might heat up a bit faster, but I kinda doubt that the difference would be significant enough to be noticeable.

It's still been mostly cloudy around here so I haven't been able to test it- but basically what I'm looking for is if the noise is fairly low up to ISO 3200 and 1 minute exposures for pictures of constellations like Orion?

ISO 3200 might be too much for 60 second exposures. You might end up with the core of the nebula blown, at least when using a fast lens. For exposures that long, you can use lower ISO. Here's a shorter, 40s exposure at a very small aperture:

See it on flickr

And does dark frame subtraction help remove a lot of it in camera?

Dark frame subtraction is for removing hot pixels, not dark current noise. It actually increases noise levels. That's why for astrophotography, dark frame subtraction is done with master dark frames that are a result of averaging many individual dark frames. This process makes sure all you are subtracting is hot pixels, and nothing else.

Oh, and obviously, temperature of the sensor makes a difference. Just leaving the camera on for a few minutes will make for increased noise levels at long exposures. Cooking a sensor for an hour in Live Composite mode will make high ISO completely useless for long exposures (talking from experience here). So a cold winter night is actually a pretty good time for long exposure photography

Astrotripper wrote:

alexisgreat wrote:

To any of you who have any of the larger Oly M43 bodies like the EM1,5, or 10, how does the EPL-6 handle dark noise at longer exposures at higher ISO compared to those cameras?

It's the same for all Olympus cameras with the 16mp Sony sensor. E-M1 is an exception, as it uses Panasonic sensor, and thus exhibits higher levels of dark current noise. See here , here and here for example. You can use google translate, but even looking at the table and histograms at the bottom of those should be enough. An E-PL5/6 might heat up a bit faster, but I kinda doubt that the difference would be significant enough to be noticeable.

Edit: I did not scroll down to the histograms, i looked at the ISO graph first. Thanks for the link, I will read it later ...

(Caution, you are mixing high ISO and long exposure here. While EM1 is king with high ISO and dynamic range, it fails partially with long exposures. At least if you don't enable darkframe subtraction.

And I doubt that the modern sonsors heat up significantly: My imporession is that during long exposures, the sensor does nothing. It sits there and waits for exposure.

Where the sensor might heat up is video readout, EVF readout with frame rate high and during live composite/live bulb when fast 1 second reradout is going on.)

It's still been mostly cloudy around here so I haven't been able to test it- but basically what I'm looking for is if the noise is fairly low up to ISO 3200 and 1 minute exposures for pictures of constellations like Orion?

ISO 3200 might be too much for 60 second exposures. You might end up with the core of the nebula blown, at least when using a fast lens. For exposures that long, you can use lower ISO. Here's a shorter, 40s exposure at a very small aperture:

See it on flickr

And does dark frame subtraction help remove a lot of it in camera?

Dark frame subtraction is for removing hot pixels, not dark current noise. It actually increases noise levels. That's why for astrophotography, dark frame subtraction is done with master dark frames that are a result of averaging many individual dark frames. This process makes sure all you are subtracting is hot pixels, and nothing else.

This is the theory, but for the average OMD user who compares sensors and who does not fiddle with averaged dark frames ...

First, hot pixel handling is roughly done by "pixel mapping" in the utility menu. Most of what we are talking about is gone after doing this step...

Second: At least the EM1 behaves more complicated: While it has no master and average frames, it actually reduces the noise by applying a single darkframe. Either it does some extra magic algorithm/noise cancelling thing (the rumored "RAW noise filter") or some low level dark current noise is still prominent even after hot pixel removal. It seems to be much better to remove the predictable noise pattern even for short exposure times.

Oh, and obviously, temperature of the sensor makes a difference. Just leaving the camera on for a few minutes will make for increased noise levels at long exposures. Cooking a sensor for an hour in Live Composite mode will make high ISO completely useless for long exposures (talking from experience here). So a cold winter night is actually a pretty good time for long exposure photography

Yes, unfortunately, cold weather seems to help

CrisPhoto wrote:

Astrotripper wrote:

alexisgreat wrote:

To any of you who have any of the larger Oly M43 bodies like the EM1,5, or 10, how does the EPL-6 handle dark noise at longer exposures at higher ISO compared to those cameras?

It's the same for all Olympus cameras with the 16mp Sony sensor. E-M1 is an exception, as it uses Panasonic sensor, and thus exhibits higher levels of dark current noise. See here , here and here for example. You can use google translate, but even looking at the table and histograms at the bottom of those should be enough. An E-PL5/6 might heat up a bit faster, but I kinda doubt that the difference would be significant enough to be noticeable.

Caution: You are mixing high ISO and long exposure here.

I'm not. I'm talking exclusively about dark current noise (the last section of the reviews I linked to)

And I doubt that the modern sonsors heat up significantly: My imporession is that during long exposures, the sensor does nothing. It sits there and waits for exposure.

That's not the case. Leave Live Composite mode for an hour (with 30 second exposures for example) and you'll see. Or set up a timelapse mode and take a few dozen long exposure dark frames and run stats on them. I did all that. The numbers are pretty straightforward. Besides, it's not necessarily the sensor itself that might be heating up. There's lots of electronics in the camera beside the sensor.

BTW, a couple years back, I read about a neat camera mod. Some guy figured out a way to cut down power to the sensor during exposure. The results were pretty amazing. Amp glow disappeared, dark current noise went down dramatically. It was a Canon compact camera, if I remember correctly. Since that time, I wondered why is this not how it works by design?

Where the sensor might heat up is video readout, EVF readout with frame rate high and during live composite/live bulb when fast 1 second reradout is going on.

That too, even more I imagine.

And does dark frame subtraction help remove a lot of it in camera?

Dark frame subtraction is for removing hot pixels, not dark current noise. It actually increases noise levels. That's why for astrophotography, dark frame subtraction is done with master dark frames that are a result of averaging many individual dark frames. This process makes sure all you are subtracting is hot pixels, and nothing else.

This is the theory, but for the average OMD user who compares sensors and who does not fiddle with averaged dark frames ...

First, hot pixel handling is roughly done by "pixel mapping" in the utility menu.

No, it's not. Pixel mapping takes care of dead or stuck pixels, as explained on Olympus website . It has nothing to do with hot pixels.

Second: At least the EM1 behaves more complicated: While it has no master and average frames, it actually reduces the noise by applying a single darkframe. Either it does some extra magic algorithm/noise cancelling thing (the rumored "RAW noise filter") or some low level dark current noise is still prominent even after hot pixel removal. It seems to be much better to remove the predictable noise pattern even for short exposure times.

I'm sure it does more than just a simple subtraction. BTW, does it affect RAW files, or is it only a JPEG thing? I never really tried it, it was the first function I disabled on my OM-D.

CrisPhoto wrote:

I own a EM5 and EM1.

Both can do great shots of night skies, but the EM1 really needs darkframe subtraction at 8 seonds and longer exposure.

EM1 versus EM5 dark current noise (with and without darkframe aka "NR")

EM5 is easier to handle regarding dark current but on the other hand it adds some magenta color cast to the hight iso/low light exposures. With darkframe and exposures at 30 seconds, I prefer the EM1. Without darkframe (star trails) and very long exposure I prefer the EM5.

I think the PL6 you mentioned is similar to my EM5 including the magenta color cast.

Would be interesting to know if ALL newer cameras with the current TruePic VII engine (EM1, EM10, EM5 II, EPL7) have better color cast handling. In this case a camera with Sony Sensor and TruePic VII engine (EM10, EPL7) would be the optimum.

Christof

That is very interesting and thanks for the graph it's quite illuminating! Where do you find dark noise data online, Christof? I have a lot of trouble finding it anywhere. Also, if dark frame subtraction is so good at reducing dark noise is there any drawback to using it (besides the fact that it takes twice the time that is.) BTW how does setting shading compensation to off help?  Thanks!

Astrotripper wrote:

alexisgreat wrote:

To any of you who have any of the larger Oly M43 bodies like the EM1,5, or 10, how does the EPL-6 handle dark noise at longer exposures at higher ISO compared to those cameras?

It's the same for all Olympus cameras with the 16mp Sony sensor. E-M1 is an exception, as it uses Panasonic sensor, and thus exhibits higher levels of dark current noise. See here , here and here for example. You can use google translate, but even looking at the table and histograms at the bottom of those should be enough. An E-PL5/6 might heat up a bit faster, but I kinda doubt that the difference would be significant enough to be noticeable.

It's still been mostly cloudy around here so I haven't been able to test it- but basically what I'm looking for is if the noise is fairly low up to ISO 3200 and 1 minute exposures for pictures of constellations like Orion?

ISO 3200 might be too much for 60 second exposures. You might end up with the core of the nebula blown, at least when using a fast lens. For exposures that long, you can use lower ISO. Here's a shorter, 40s exposure at a very small aperture:

See it on flickr

And does dark frame subtraction help remove a lot of it in camera?

Dark frame subtraction is for removing hot pixels, not dark current noise. It actually increases noise levels. That's why for astrophotography, dark frame subtraction is done with master dark frames that are a result of averaging many individual dark frames. This process makes sure all you are subtracting is hot pixels, and nothing else.

Oh, and obviously, temperature of the sensor makes a difference. Just leaving the camera on for a few minutes will make for increased noise levels at long exposures. Cooking a sensor for an hour in Live Composite mode will make high ISO completely useless for long exposures (talking from experience here). So a cold winter night is actually a pretty good time for long exposure photography

Very nice image! I think you can see stars down to about 14th mag in it, no?  Thanks about dark frame subtraction, I did not know that.  It sounds like what we have to do for CCD cameras, you need to take a "library" of darks at different temperatures.  I haven't used Live Composite mode yet- is that only for star trails?  This is the peak time for astrophotography here, arctic air is finally here!  It would be nice if the wind lowered a bit though lol.

An interesting fact I just learned is that all Sony sensors produced from 2012 onwards have an "onboard" dark current suppressor built into the electronics.  This might explain some of the differences.

Real world comparisons posted here with different Oly cameras.

http://www.dpreview.com/forums/post/57025873

I know there are some there from the EM1 and EM10- not sure if any from the EM5 are in there but they should be.

I posted that in a thread in the astrophotography forum because people were telling me that MFT cameras have too much dark noise to be used for astrophotography.  They told me ISO above 800 cannot be used.  I found images of very good quality all the way to ISO 3200 (at 30 second exposures) and ISO 1600 (1 minute exposures x10 stack) with both the EM1 and the EM10.  The person who was saying that MFT cameras have too much dark noise to be useful above ISO 800 for long exposures has an EPL-5, that's why I was wondering if there is a difference with the smaller bodies vs the larger ones- but he also had dark frame subtraction turned off.

alexisgreat wrote:

Astrotripper wrote:

alexisgreat wrote:

It's still been mostly cloudy around here so I haven't been able to test it- but basically what I'm looking for is if the noise is fairly low up to ISO 3200 and 1 minute exposures for pictures of constellations like Orion?

ISO 3200 might be too much for 60 second exposures. You might end up with the core of the nebula blown, at least when using a fast lens. For exposures that long, you can use lower ISO. Here's a shorter, 40s exposure at a very small aperture:

See it on flickr

Very nice image! I think you can see stars down to about 14th mag in it, no?

Nah, I don't think so. 12 mag for sure, maybe even 13, but 14 would require some stacking and most likely a longer exposure. But in general, I'm always pretty amazed how "deep" you can peek even with a single exposure.

Thanks about dark frame subtraction, I did not know that. It sounds like what we have to do for CCD cameras, you need to take a "library" of darks at different temperatures.

It's the same for modern consumer cameras as well. I have a whole library of darks taking space on external hard drive

If you'll have some time on your hands, I would recommend having a go at stacking. Even if you don't have a tracking mount, you can do some interesting things as long as you have a fast lens. The closer you stick to the area near the celestial pole, the longer the exposures you can take without any tracking. It's unfortunate that this area is lacking in impressive objects, at least in northern hemisphere. But pointing your camera at Polaris and taking a bunch of shots is the easiest way to have some material to practice stacking and subsequent post-processing. And if you want some Milky Way, Cassiopeia is probably the best choice for starters.

You can have a look at my recent thread on astrophotography here .

I haven't used Live Composite mode yet- is that only for star trails?

For astro, yes, that's pretty much it. Normally, it's also fantastic for light painting. Or you can combine both.

This is the peak time for astrophotography here, arctic air is finally here! It would be nice if the wind lowered a bit though lol.

I've been lucky in this regard. Not only did new year start with clear skies, the winds died out at the same time. And I have not seen a clear night sky in months previous to that. Not to mention crazy winds for the past two or three months.

alexisgreat wrote:

Real world comparisons posted here with different Oly cameras.

http://www.dpreview.com/forums/post/57025873

I know there are some there from the EM1 and EM10- not sure if any from the EM5 are in there but they should be.

I posted that in a thread in the astrophotography forum because people were telling me that MFT cameras have too much dark noise to be used for astrophotography. They told me ISO above 800 cannot be used. I found images of very good quality all the way to ISO 3200 (at 30 second exposures) and ISO 1600 (1 minute exposures x10 stack) with both the EM1 and the EM10. The person who was saying that MFT cameras have too much dark noise to be useful above ISO 800 for long exposures has an EPL-5, that's why I was wondering if there is a difference with the smaller bodies vs the larger ones- but he also had dark frame subtraction turned off.

It's a usual trade-off of a smaller sensor. You will obviously get more noise from it. But at least for astrophotography, you can counter that by stacking. Got more noise? Acquire more data for stacking. You can get really good results from MFT cameras if you get the hang of it. Obviously, optics is a very important aspect as well. It's not gonna work if all you have is a slow kit zoom lens.

You know, there's always something better. And at the end of that road, is dedicated equipment that costs thousand of dollars per piece

Astrotripper wrote:

alexisgreat wrote:

Real world comparisons posted here with different Oly cameras.

http://www.dpreview.com/forums/post/57025873

I know there are some there from the EM1 and EM10- not sure if any from the EM5 are in there but they should be.

I posted that in a thread in the astrophotography forum because people were telling me that MFT cameras have too much dark noise to be used for astrophotography. They told me ISO above 800 cannot be used. I found images of very good quality all the way to ISO 3200 (at 30 second exposures) and ISO 1600 (1 minute exposures x10 stack) with both the EM1 and the EM10. The person who was saying that MFT cameras have too much dark noise to be useful above ISO 800 for long exposures has an EPL-5, that's why I was wondering if there is a difference with the smaller bodies vs the larger ones- but he also had dark frame subtraction turned off.

It's a usual trade-off of a smaller sensor. You will obviously get more noise from it. But at least for astrophotography, you can counter that by stacking. Got more noise? Acquire more data for stacking. You can get really good results from MFT cameras if you get the hang of it. Obviously, optics is a very important aspect as well. It's not gonna work if all you have is a slow kit zoom lens.

You know, there's always something better. And at the end of that road, is dedicated equipment that costs thousand of dollars per piece

Yep, plus 4/3 sensors aren't much smaller than APS-C plus I can argue that 4:3 aspect ratio is better for AP!  I got this camera firstly because I wanted a really lightweight combo to couple to my telescope(s) and the weight of the EPL-6 is almost the same as a CCD camera (since you dont need a flash or an EVF to be attached all the time.)  I need to get 4/3 attachments to connect it to a telescope though and I want to know if I can use my 1.25" light pollution filters with it without much vignetting.  How close to the sensor can one get the filter using telescope attachments? I know the flange distance is 19.25mm but I'm hoping that I can get the sensor to filter distance to about 35mm when using my f/6.3 reducer/corrector and to about 54mm when using my Nexstar 8 at f/10.  That would mean no vignetting.

alexisgreat wrote:

...

That is very interesting and thanks for the graph it's quite illuminating! Where do you find dark noise data online, Christof? I have a lot of trouble finding it anywhere. Also, if dark frame subtraction is so good at reducing dark noise is there any drawback to using it (besides the fact that it takes twice the time that is.) BTW how does setting shading compensation to off help? Thanks!

I did some test shots and evaluated the noise with RawDigger.

My conclusion is that darkframe subtraction works better than expected on my EM1 and more or less as expected with the EM5.

Shading compensation is a big problem in AP (if you use a mFT lens). The picture borders are brightened automatically and you get very odd frame patteren surrounding your photo. I think the algorithm Olympus is using works only for daylight shots and works very bad with low light.

You can test it easily, take a mFT lens, open the aperture and take a darkframe at ISO 12800. I bet you will be surprised ...

Here is an old thread discussing the issue:

http://www.dpreview.com/forums/post/52652493

As shading compensation is done on RAW data, it is very hard to restore a shot if you enable shading compensation by accident.

CrisPhoto wrote:

alexisgreat wrote:

...

That is very interesting and thanks for the graph it's quite illuminating! Where do you find dark noise data online, Christof? I have a lot of trouble finding it anywhere. Also, if dark frame subtraction is so good at reducing dark noise is there any drawback to using it (besides the fact that it takes twice the time that is.) BTW how does setting shading compensation to off help? Thanks!

I did some test shots and evaluated the noise with RawDigger.

My conclusion is that darkframe subtraction works better than expected on my EM1 and more or less as expected with the EM5.

Shading compensation is a big problem in AP (if you use a mFT lens). The picture borders are brightened automatically and you get very odd frame patteren surrounding your photo. I think the algorithm Olympus is using works only for daylight shots and works very bad with low light.

You can test it easily, take a mFT lens, open the aperture and take a darkframe at ISO 12800. I bet you will be surprised ...

Here is an old thread discussing the issue:

http://www.dpreview.com/forums/post/52652493

As shading compensation is done on RAW data, it is very hard to restore a shot if you enable shading compensation by accident.

Thanks, it is good we can turn shading compensation off in these cameras!  It is a pity you dont have the EPL-5/6 then we could have compared the dark noise between the smaller bodies and the larger ones.  What is the highest ISO and longest exposure you would use with these cameras for AP?

alexisgreat wrote:

---

Thanks, it is good we can turn shading compensation off in these cameras! It is a pity you dont have the EPL-5/6 then we could have compared the dark noise between the smaller bodies and the larger ones. What is the highest ISO and longest exposure you would use with these cameras for AP?

I think the sensors are very similar, there is not much difference between EM5, PM2, PL5 and PL6. Same generation of cameras.

I think its interesting to know how EM5 II or EM10 II behave, these might use newer sensors and for sure they you a newer TruePic firmware.

alexisgreat wrote:

Astrotripper wrote:

It's a usual trade-off of a smaller sensor. You will obviously get more noise from it. But at least for astrophotography, you can counter that by stacking. Got more noise? Acquire more data for stacking. You can get really good results from MFT cameras if you get the hang of it. Obviously, optics is a very important aspect as well. It's not gonna work if all you have is a slow kit zoom lens.

You know, there's always something better. And at the end of that road, is dedicated equipment that costs thousand of dollars per piece

Yep, plus 4/3 sensors aren't much smaller than APS-C plus I can argue that 4:3 aspect ratio is better for AP! I got this camera firstly because I wanted a really lightweight combo to couple to my telescope(s) and the weight of the EPL-6 is almost the same as a CCD camera (since you dont need a flash or an EVF to be attached all the time.)

Ahh, I see, we're talking about a more serious attempts at astrophotography. The E-PL is a nice little camera to attach to a telescope. And a tilting screen is a big plus as well

I need to get 4/3 attachments to connect it to a telescope though and I want to know if I can use my 1.25" light pollution filters with it without much vignetting. How close to the sensor can one get the filter using telescope attachments? I know the flange distance is 19.25mm but I'm hoping that I can get the sensor to filter distance to about 35mm when using my f/6.3 reducer/corrector and to about 54mm when using my Nexstar 8 at f/10. That would mean no vignetting.

This can be tricky. Your usual T2-MFT adapters are actually quite long. Mine is something like 40mm or so. It was annoying me, because when I had the camera attached to my newtonian telescope with this long adapter, the tube on the side where you attach an eyepiece/camera (sorry, can't remember what it's called in English) was almost entirely inside the telescope tube, partly obstructing the primary mirror. So I made my own, "slim" adapter by combining parts of two completely different adapters. I'll try posting some photos of it later.

Astrotripper wrote:

alexisgreat wrote:

Astrotripper wrote:

It's a usual trade-off of a smaller sensor. You will obviously get more noise from it. But at least for astrophotography, you can counter that by stacking. Got more noise? Acquire more data for stacking. You can get really good results from MFT cameras if you get the hang of it. Obviously, optics is a very important aspect as well. It's not gonna work if all you have is a slow kit zoom lens.

You know, there's always something better. And at the end of that road, is dedicated equipment that costs thousand of dollars per piece

Yep, plus 4/3 sensors aren't much smaller than APS-C plus I can argue that 4:3 aspect ratio is better for AP! I got this camera firstly because I wanted a really lightweight combo to couple to my telescope(s) and the weight of the EPL-6 is almost the same as a CCD camera (since you dont need a flash or an EVF to be attached all the time.)

Ahh, I see, we're talking about a more serious attempts at astrophotography. The E-PL is a nice little camera to attach to a telescope. And a tilting screen is a big plus as well

I need to get 4/3 attachments to connect it to a telescope though and I want to know if I can use my 1.25" light pollution filters with it without much vignetting. How close to the sensor can one get the filter using telescope attachments? I know the flange distance is 19.25mm but I'm hoping that I can get the sensor to filter distance to about 35mm when using my f/6.3 reducer/corrector and to about 54mm when using my Nexstar 8 at f/10. That would mean no vignetting.

This can be tricky. Your usual T2-MFT adapters are actually quite long. Mine is something like 40mm or so. It was annoying me, because when I had the camera attached to my newtonian telescope with this long adapter, the tube on the side where you attach an eyepiece/camera (sorry, can't remember what it's called in English) was almost entirely inside the telescope tube, partly obstructing the primary mirror. So I made my own, "slim" adapter by combining parts of two completely different adapters. I'll try posting some photos of it later.

Thanks I appreciate it! Is there somewhere in this combo where a 1.25" filter can be threaded? I dont think the usual Celestron parts allow this, part numbers 93625 and 93633-A. Agena Astro has some that might work though.

This is what someone said to me in the AP forum:

neither of those celestron adapter says in the description they allow for 1.25" filters. the SCT to T thread certainly would not. The 93625 1.25" adapter looks like it has internal threads that are there for stray light baffling, and typically also cut to fit 1.25" filter accessories... but i dont see or read any description that it does... other than there is a similar adapter with a 2x magnifying barlow at the end that clearly threads on... #93640

http://www.celestron.com/browse-shop/astronomy/astroimaging-accessories/t-rings-and-adapters/125-universal-barlow-and-t-adapter

these adapter from blue fireball and baader certainly do fit 1.25 filters as they say in the description.

http://agenaastro.com/blue-fireball-1-25-prime-focus-t-adapter.html

http://agenaastro.com/baader-1-25-nosepiece-t-2-adapter-t2-14-2458105.html

you do not need, or should not need to use a diagonal with your camera. it will likely add too much back focus distance, youll never reach focus. and make it considerably less stable.

i would stick with the #93633-A SCT to T thread adapter, and just get the MFT to T thread adapter. it will be overall more stable and direct and not vignette the sensor.

if you really want to put a 1.25" filter in the system, it looks like you can use this adapter which should be perfect for you.

http://agenaastro.com/blue-fireball-t-t2-male-m28-5-female-thread-adapter-t-10.html

alexisgreat wrote:

Astrotripper wrote:

alexisgreat wrote:

I need to get 4/3 attachments to connect it to a telescope though and I want to know if I can use my 1.25" light pollution filters with it without much vignetting. How close to the sensor can one get the filter using telescope attachments? I know the flange distance is 19.25mm but I'm hoping that I can get the sensor to filter distance to about 35mm when using my f/6.3 reducer/corrector and to about 54mm when using my Nexstar 8 at f/10. That would mean no vignetting.

This can be tricky. Your usual T2-MFT adapters are actually quite long. Mine is something like 40mm or so. It was annoying me, because when I had the camera attached to my newtonian telescope with this long adapter, the tube on the side where you attach an eyepiece/camera (sorry, can't remember what it's called in English) was almost entirely inside the telescope tube, partly obstructing the primary mirror. So I made my own, "slim" adapter by combining parts of two completely different adapters. I'll try posting some photos of it later.

Thanks I appreciate it! Is there somewhere in this combo where a 1.25" filter can be threaded? I dont think the usual Celestron parts allow this, part numbers 93625 and 93633-A. Ageena Astro has some that might work though.

This is what someone said to me in the AP forum:

neither of those celestron adapter says in the description they allow for 1.25" filters. the SCT to T thread certainly would not. The 93625 1.25" adapter looks like it has internal threads that are there for stray light baffling, and typically also cut to fit 1.25" filter accessories... but i dont see or read any description that it does... other than there is a similar adapter with a 2x magnifying barlow at the end that clearly threads on... #93640

http://www.celestron.com/browse-shop/astronomy/astroimaging-accessories/t-rings-and-adapters/125-universal-barlow-and-t-adapter

I have something like that, but not Celestron. My Sky-Watcher telescope came with a Barlow lens that looks just like that. It has a T thread and can be connected to a T-Ring, and the barlow lens itself is screwed on using a standard filter thread. So you can replace it with a filter of choice. And even the chrome part of the tube is detachable and can be replaced by one from one of the kit eye-pieces. The big question here is, does this Celestron also use a standard filter thread, or not? I have no idea. Maybe you could ask on an astronomy forum like cloudynights, there's bound to be someone with this particular barlow lens that could confirm or deny.

Can't really comment on those other solutions. I don't even know if it would be better to have the filter further away from the sensor (in which case a threaded nosepiece will work) or closer to it (in which case the low profile male/female T2 adapter with a filter thread should do the job), so can't help you much with this.

But I agree with the advice to not use a diagonal when attaching a camera. You definitely don't want to do that.

Astrotripper wrote:

alexisgreat wrote:

Astrotripper wrote:

It's a usual trade-off of a smaller sensor. You will obviously get more noise from it. But at least for astrophotography, you can counter that by stacking. Got more noise? Acquire more data for stacking. You can get really good results from MFT cameras if you get the hang of it. Obviously, optics is a very important aspect as well. It's not gonna work if all you have is a slow kit zoom lens.

You know, there's always something better. And at the end of that road, is dedicated equipment that costs thousand of dollars per piece

Yep, plus 4/3 sensors aren't much smaller than APS-C plus I can argue that 4:3 aspect ratio is better for AP! I got this camera firstly because I wanted a really lightweight combo to couple to my telescope(s) and the weight of the EPL-6 is almost the same as a CCD camera (since you dont need a flash or an EVF to be attached all the time.)

Ahh, I see, we're talking about a more serious attempts at astrophotography. The E-PL is a nice little camera to attach to a telescope. And a tilting screen is a big plus as well

I need to get 4/3 attachments to connect it to a telescope though and I want to know if I can use my 1.25" light pollution filters with it without much vignetting. How close to the sensor can one get the filter using telescope attachments? I know the flange distance is 19.25mm but I'm hoping that I can get the sensor to filter distance to about 35mm when using my f/6.3 reducer/corrector and to about 54mm when using my Nexstar 8 at f/10. That would mean no vignetting.

This can be tricky. Your usual T2-MFT adapters are actually quite long. Mine is something like 40mm or so. It was annoying me, because when I had the camera attached to my newtonian telescope with this long adapter, the tube on the side where you attach an eyepiece/camera (sorry, can't remember what it's called in English) was almost entirely inside the telescope tube, partly obstructing the primary mirror.

I'm interested. I tried a t2 adapter and had the same issue. In fact I would have had to move my mirror quite a bit to achieve focus. I decided to return it and haven't made any serious attempts at astrophotography since then.

I've got a 5" somewhat fast Newt and I still have thoughts of buying a paracorr and a GEM mount and seeing what it can do.

So I made my own, "slim" adapter by combining parts of two completely different adapters. I'll try posting some photos of it later.

Astrotripper wrote:

So I made my own, "slim" adapter by combining parts of two completely different adapters. I'll try posting some photos of it later.

Here it goes. Some photos first:

From left to right: home-made adapter, store bought adapter, barlow lens with filter on one end and T thread on the other

E-PL1 with the big adapter

and with the home-made adapter, a pretty big difference

And with the barlow lens attached, ready to be mounted onto the telescope (1.25" nosepiece)

Top-down view of home-made T-ring

and a side view, where it's clearly visible it's been hacked together from two different adapters

So, the base for this slim T-ring is a cheap chinese L39 to Micro 4/3 lens mount adapter. This is the outer shell. I choose this one specifically, because I knew (from the photos) that it was a two part thing with the actual L39 screw mount being a separate part held in place by three little screws (one of which is visible in last photo). I figured I could simply replace that internal part with analogous part from another T-Ring, effectively replacing that L39 tread with T thread.

That donor adapter was Kipon's T-Ring for Sony Alpha DSLRs, which was the first camera I mounted onto my telescope. It was also a two piece adapter with the T-threaded part held in place by three screws, so it was trivial to extract it. However, that little bugger was slightly too large to fit into it's new home, so I had to sand it down to appropriate diameter. And as illustrated, it was also a bit thicker, so it's not flush with the outer shell, but it doesn't matter. I've had no problems with it so far, and I was even using it in freezing temperatures.