Terrible disappointment with first attempt...

[benjamind2014]

I just hooked up my Samsung NX300m mirrorless camera to my microscope via the T2 to eyetube adapter.

At first I decided to look at the halftone printing on a sheet of magazine and used some incident light to test things out.

Now when I look at the camera view on the display it looks quite nice. But when I take the photo it makes a snapping noise and then I get a few seconds of the preview of the photo I just took.

The photo is blurry and is darker than what I thought it would be.

Is there anything that can be done? I couldn't believe how awful the images looked. Dark and blurry whereas on the live view on the NX300m's display looked reasonably good.

I would appreciate any help. Is there really any way to stop the vibrations at least, they are by far my biggest concern but also the darker image is also a concern.

I thought the NX300m being mirrorless was supposed to eliminate this problem. I thought it would prevent vibration. I even used timed shot and still the same problem. Could I please have some advice.

[Charles Krebs]

The "too dark" part is easy... I strongly suggest using manual exposure and then checking the histogram after a test shot to make any needed exposure changes. Some cameras seem to do pretty well in "auto-exposure" on a microscope, others do poorly. Sometimes a camera will display what appears to be a good exposure in live view, but the resulting photo is over or underexposed. Ultimately I really think manual exposure, and referencing the histogram after a test shot or two is the best method to use for exposure.

I thought the NX300m being mirrorless was supposed to eliminate this problem. I thought it would prevent vibration. I even used timed shot and still the same problem.

Unfortunately that is not the case. Most mirrorless cameras actually have two mechanical shutter movements before an exposure begins.

The exposure sequence goes like this:
The shutter is open for live view. When you hit the shutter release the mechanical shutter closes, the sensor "clears" electronically, and then the exposure is begun by the mechanical first shutter curtain re-opening. So you have both of these vibration causing shutter movements occurring rapidly one after the other just before the exposure starts. (This happens very rapidly and it is hard to distinguish that two mechanical actions are occurring). At the end of the exposure the second mechanical shutter curtain closes, but any vibration this causes is after the exposure ends. The vibration effects are especially noticeable on a microscope image (and often most problematic with shutter speeds in the 1/2 to 1/125 second range).

In order to check if this is indeed the problem, set up a shot where the exposure time needed will be about 3 seconds, or even slightly longer. (You may need to put some type of neutral density over the microscope light port if using transmitted light. For reflected light just move the light source farther away). If the problem is shutter induced vibration it will usually "dampen out" in a small fraction of a second, giving you a vibration-less exposure for the vast bulk of the exposure time. This procedure will let you know if the shutter is the cause of your problem.

This the reason why we love to have a fully electronic first shutter curtain (EFSC") on microscope mounted cameras.

This test is a bit dated but still quite relevant:
http://krebsmicro.com/Canon_EFSC/index.html

[benjamind2014]

Hi Charles,

I really appreciate this response. It really makes things much easier to grasp.

I think the vibrations are going to be hard to deal with but maybe I will be able to get an answer from the vendor who sold me the Samsung T2 adapter.

What I really fail to understand is why isn't it just possible to take a snapshot of the live view? Now I think that would really help the problem or even entirely eliminate it.

Best,
Ben