I have been looking for a video like this for days! Easily the best video on this topic

@DenimSuitPhoto

2 жыл бұрын

Awesome, thank you!

Better explained than this impossible. Brilliant

@DenimSuitPhoto

2 жыл бұрын

thanks for watching!

Thanks Scott. Massively helpful video.

@DenimSuitPhoto

3 жыл бұрын

Glad it was helpful!

Nice Scott... Thanks

@DenimSuitPhoto

3 жыл бұрын

Thanks for watching!

very informative video! Thanks for making calibration frames easier to understand and take!

@DenimSuitPhoto

2 жыл бұрын

Glad you enjoyed it!

You are an excellent instructor!

@DenimSuitPhoto

3 жыл бұрын

I appreciate that!

Thanks for making this awesome video. When I was taking IR pictures with Kodak HIE film, (I really miss this awesome film). I had to be really careful removing and spooling the roll. Even a luminous watch face would cloud the film. In the darkroom, I used a film changing bag. Nothing bar X-rays and Gamma rays are going to get through one of these bags. I still have mine and it's perfect for dark and bias frames.

@DenimSuitPhoto

3 жыл бұрын

Thanks for sharing!

Hope you are doing well, Scott!

@DenimSuitPhoto

3 жыл бұрын

I am doing pretty good Justin! How are you?

Great video Scott One question that never seem to get addressed, when taking Flats with a dedicated astronomy camera what should I set the exposure to?

@DenimSuitPhoto

Жыл бұрын

I was told to always use aperture priority. I let the camera decide what the exposure should be but generally speaking it should be exposed in the middle if you're looking at a histogram

@arthurkaye8999

Жыл бұрын

@@DenimSuitPhoto thanks for that. I have been experimenting in taking flat frames with a home made light panel. Like you suggested, by looking at the histogram i am finding what works best. Around 1-2 second exposures.

Hi Scott. Great little tutorial. Can you comment on Dark Flats? There seems to be some confusing information on the internet about using Dark Flats in lieu of Bias. The confusion is whether it is beneficial for CCD or CMOS sensors. I am using a Nikon D7500 for my astrophotography. Thanks

@DenimSuitPhoto

3 жыл бұрын

Dark Flat frames are like Darks but for your Flats instead. I guess the theory is that Flat frames aren't immune to sensor noise, so taking a dark flat frame will help clean up the corrections coming from the Flats series. You would take them identically like your Flats, but with the lens/scope covered. Whether or not they're useful is entirely dependent on the software you're using. I'm only using SIRIL these days, and SIRIL doesn't include dark flats in its processing. Deep Sky Stacker (PC only) however, can utilize dark flats. As for whether they're useful or not, you'll have to process the series and evaluate the results individually. I would probably add dark flats to the workflow rather than swap them out for bias frames. But the only way to know for sure is to check the results. Every sensor is going to capture the data differently, and need varying degrees of calibration.

@febsat

3 жыл бұрын

@@DenimSuitPhoto thanks for that quick response

@DenimSuitPhoto

3 жыл бұрын

@@febsat no problem!

Very helpful video The only term I don’t understand is light frame I hear this other videos and no one explains what it is . To me sounds like the object are taking like m42…! Is that right? Thanks.

@DenimSuitPhoto

Жыл бұрын

You are correct. A light frame is the actual photo of the thing youre taking

Very informative video! Keep up the good work. I find taking darks very time consuming. Can I create a bunch of them, make a master dark, and reuse them the next time I use the same objective (E.g. Samyang 135mm f/2) again? Or does it have to be so strict as you are saying in your video @2:05?

@DenimSuitPhoto

2 жыл бұрын

Darks have to be taken at the same sensor temperature as the Lights. So with a DSLR this is obviously functionally impossible, so you have to get as close as you can, which is why darks should be taken right after your light frames. If the temperature between darks and lights is too far off, they wont work properly. The only correct way to do as you suggest (take a bunch of darks and re-use them) is if you could somehow keep the sensor temperature at the same value, whenever you shoot. But the only way to do that is with a dedicated cooled astro camera, which would allow you to set the temperature of the sensor.

@pmodi64

2 жыл бұрын

@@DenimSuitPhoto Love your videos. I have seen discussions that suggest if you dither between images then you don't need to take dark frames. Have you tried it? What's your take on dithering?

@DenimSuitPhoto

2 жыл бұрын

@@pmodi64 the portable mounts I currently use are not the best platforms for dithering. But if you have a solid equatorial mount, dithering is a fantastic way to reduce noise in your images. The only way to know if you don’t require darks is to try both with and without, using your current setup. Some cameras may need darks, some might not. It also depends on the environment you’re shooting in, and how much pixel peeping you’re gonna do. So there’s not really a definitive answer. But if you CAN dither, you should definitely give it a try

Very informative video, just 1 question, why not put correction in lightroom - distortion and chromatic aberration, at least distortion to flat image ? i see a lot of tutorials and no1 mention of it, is it not important ?

@DenimSuitPhoto

2 жыл бұрын

That’s because the correction applied in Lightroom isn’t for your exact lens. It’s an average of sampled lenses so it will never work as well as taking flats, which are unique to your camera-lens-focus. Nothing can replicate that like flat frame. And they’re not to difficult to take, so that’s why everyone just ignores using the lens corrections in software.

how do you get a white background on tablet or laptop

@DenimSuitPhoto

9 ай бұрын

Great question. You can open the notes app on any IOS device, google "white backround" and download a photo to open your devices default photo viewer, or make large 2x3ish white jpeg in photoshop or paint and sav it for later use.

Great reference video for us new astro shooters. Quick question - what should the shutter speed be for your flat frames? You call out ISO and aperture as the light frames, but what should the shutter speed be? Thanks!

@DenimSuitPhoto

3 жыл бұрын

Ooooh good question, but unfortunately there's too many variables with flats to give you an accurate number. Its very dependent on the ISO and Aperture you used in your Lights frames. Another variable still would be the brightness of the screen you are using to project the white image. That's why best to use an automatic camera function like Aperture Priority. Just looking at 20 random "flats" folders in my library and I see everything from 0.5/sec to 1/1000sec. I hope this helps.

@bbidnick

3 жыл бұрын

@@DenimSuitPhoto Thanks, that clears things up.

@DenimSuitPhoto

3 жыл бұрын

@@bbidnick thanks for watching!

In using a DSLR and 135 mm lens, are the calibration frames shot in RAW or JPG?

@DenimSuitPhoto

Жыл бұрын

I always shoot raw

Hi Scott, I'm just starting to look into the processes required for astrophotography. If one would usually shoot dark frames at the same ISO and same exposure length could one just save those files for future use? Also, since the lens cap is on for bias and dark frames I can just see setting the camera inside on a stable platform and use a cameras internal intervalometer to shoot off "x" numbers of frames. Sorry, if this a dumb question.

@DenimSuitPhoto

Жыл бұрын

Not a dumb question at all! It is not recommended to save these files for later use because the darks frames working correctly are also mostly temperature dependent. Meaning they need/should be captured at the same temperature as your light frames. Thats difficult enough with a consumer camera because we have no control over the temperature of the camera sensor. So each shoot you do with your camera will have unique noise characteristics based on the ambient temperature. Taking the dark frames right after your light frames session is the closest approximation we can make to get the dark frame noise to best resemble the light frame noise, which will help cancel it out. Based on this I would not recommend taking the camera indoors and doing dark frames. The environment indoors could be vastly different than the environment outside where your light frames were captured, and thus would not be a match to cancel each other out.

@kathieodonnell6882

Жыл бұрын

@@DenimSuitPhoto Thanks for the quick reply. Great explanation, I understand what you're saying.

Should we attach our lens while taking dark frames for a dslr ??

@DenimSuitPhoto

Жыл бұрын

totally not necessary

@pruthuvanara1243

Жыл бұрын

@@DenimSuitPhoto I'm hearing that for first time from someone, everyone recommends not to change the setup or break the rig up

@DenimSuitPhoto

Жыл бұрын

@@pruthuvanara1243 As long as youve already taken your lights (and flats) you do not need anything attached to your camera to take darks. The ambient (and therefore sensor) temperature should be as close as possible to get the best results. That is the only thing you should be worried about using a non-cooled camera for astrophotography.

Flat frames - no T shirt when you use a tablet?

@DenimSuitPhoto

9 ай бұрын

I have found that at that distance, a t-shirt is negligible is diffusing the light in any way, and, the tablet screen is out of focus enough at that distance to not need to use any diffusion material