t mode Long exposure mode XT-2

[AntJames]

Hi,

 I’m trying long exposure Photography using a 10 stop filter. 
I have 2 issues- firstly with noise reduction selected ‘ON’ and during an overcast day shooting a fast flowing river in Wales and using ‘B’ mode with cable release the actual exposure was 4 minutes, this was achieved by trying an exposure at say 1 min which resulted in black and thus increasing the time until it looked right on the scene and this History gram confirmed this. I  then have to wait another 4 minutes for processing to take place removing ‘hot pixels’, which I get.
But here’s the thing once noise reduction is turned ‘OFF’ the initial exposure drops dramatically to 45” ! 
I understand the processing isn’t being applied after but why has the initial exposure of 4 mins with it on, dropped to 45” whilst off ? 
At the time I was surprised it was as long as 4’ .

what’s going on to make it sooooo long ? 

[jerryy]

That does sound a bit odd, it could be a one time glitch or due to how much the lighting conditions changed while you were working on the image, even big stoppers can let in a lot more light for a moderate change in lighting conditions.

(You initially mention two concerns, what was the second one?)

Try this, repeat the setup, taking a shot with nr turned on and go through the full process) Turn it off and take a shot. Turn it back on and see if the shot time jumps way back up again, all the while making sure to note the lighting changes.

 

On a related note, there is a way to get the same value of using nr via your image processing software (GIMP, Affinity Photo, Photoshop, etc., any of those that support layers with blend modes). Take your shots with nr turned off, then put the lens cap on, take a shot using the exact same parameters as you used for your regular images.— same time, iso, f-stop, etc.. Bring both the regular image and the cap-on image into your processor as layers, the stacking order will depend on your software, but it will typically be with the cap-on image above the regular image. Set the blend mode for the cap-on layer to “subtract”. This will remove hot pixels, etc. from your regular image just like the in-camera method does. But you save a lot of very valuable time while you are on site. The drawback to this is that you need to do this before you turn the camera off after taking the image set, and also take one now and then as you are going if the camera is left on for very long times. One other thing to note, if you are going to change any of the iso or time settings etc., you need to take a on-cap image before making changes to the settings.

[AntJames]

Thanks Jerry , I like the sound of NR in post I will definitely look into that. 
on the subject of the long exposures it is always like this , around 4’ with NR on and a more normal 45” with it off.

The 2nd dilemma you ask about is I tried using T mode and it just takes the picture, as in ‘click’

job done, so if the exposure is set to 1.5 minutes it just goes click, no countdown.

I have shutter set to Manual, Manuel aperture, iso 200 and shutter set to ‘T’. 
Any ideas ? 

Edited October 9, 2021 by AntJames

[jerryy]

T Mode stands for timed mode, how long you want the shutter to be open. You need to set it to a time. Usually you use one of the dials, front or back, to set the time you wish to use. T mode is a long exposure setup without needing to use a remote shutter release in B Mode or dig through the menus to set up interval shooting.

It sounds like it is working correctly, it is just using the baked in default time. Once you set the time, and press the shutter button, it should go click and take a timed-length photo, then shut the shutter, you should hear another click as the shutter closes. Using a remote release allows you to take a second to let any vibrations in your tripod to settle, and then trip the shutter without causing new vibrations.

You can also dig in the menus to set up interval timed shooting with only a few shots, you can set an interval between the shots as well as a ‘wait before starting’ time.

Edited October 9, 2021 by jerryy

[AntJames]

Yep I’m aware it’s Time mode and like I said what ever time I set using the rear dial, let’s say 1.5 minutes once the shutter button is pressed rather than it starting the time it just takes a photo -‘click ‘

At normal kind of SS say 1/250th .

I've looked through the menus trying to figure out why it’s not opening on first click and shutting on 2nd but no joy. 

[jerryy]

Okay, that makes it clearer, the way you wrote about no countdown sounded like you wanted it to act as a countdown timer before snapping a photo, which is an entirely different thing. T Mode should start click right away, but stay open for the length you set.

Did you buy this one used? Have you updated the firmware to the latest version? It sounds like there are a couple of things that may broken. If you got this body new, you may find it worthwhile to get the dealer to check it over while it is still under warranty.

p.s. https://fujifilm-dsc.com/en/manual/x-t2/taking_photo/shooting_mode/index.html

Just to double check, you do have it in one of the p, s, a, m shooting modes? It sounds like you do, but sometimes one of the dials jumps into a position it should not.

Edited October 10, 2021 by jerryy

[TheGreenMan]

Other things you can do to clean up the image:

In astrophotography Along with taking a dark, cap-on, photo of the same length with the same settings to subtract from your actual image you can also take a "twilight sky flat". This can compensate for pixels on the sensor that are more or less sensitive than others. A description of the process can be found here: https://physics.bgsu.edu/~layden/ASTRO/OBSERVATORY/obs_instr_skyflats.htm

Another thing you can do, though I'm not sure off-the-shelf cameras have the ability, is take a bias image/frame, or a picture of no exposure time. This will let you subtract the noise of the sensor itself. I think the best you could do is, with the cap on, take a picture of the shortest exposure you can.

 

Another resource: https://practicalastrophotography.com/a-brief-guide-to-calibration-frames/