hi, i have a question, u mentioned to lock up mirror to reduce vibration.. i have nikon d5300 and is it possible to do that on my dslr too? i have never heard that it is possible to shoot like that with DSLRs

@GarnettLeary

5 жыл бұрын

The D5300 doesn’t offer mirror lock up unfortunately. There is an alternative however. Prior to lock up astrophotographers would use something like a playing card. You start your exposure with the card held in front of the lens for a second or two and then place it back the last second or two. By doing this you will eliminate any internal vibration caused by the mirror swinging up. A large piece of cardboard could be used for a telescope. Especially older dslr’s the mirror slap is very noticeable in a night shot. The higher the focal length the worse it is. I hope this helped. Clear skies.

@ikaabuladze6510

5 жыл бұрын

@@GarnettLeary thanks, clear skies as well

I've watched 8 videos on the subject and this is the best.

@GarnettLeary

4 жыл бұрын

Thank you for that. It was my goal to be short and meaningful.

Thanks for posting, Garnett. This is completely counterintuitive and I would have never assumed that. I have the T3 model and will have to try this out.

@GarnettLeary

6 жыл бұрын

I know right. Most people would immediately say it’s a silly statement until they try it. I expect pre-test criticism. Please let me know your results. Clear skies.

thanks so much for putting this so easy! im looking forward to a clear night to test my camera!

@GarnettLeary

3 жыл бұрын

Thank you for watching. I hope you have many clear ones.

You don’t sound like Eugene to me and I’m a big Walking Dead fan. Keep up the great work. These videos are helpful.

@GarnettLeary

2 жыл бұрын

Thank you

I also shoot with a Canon 6D. It really is a beast when it comes to noise peformance. Thanks for the video :)

@GarnettLeary

4 жыл бұрын

Thanks for watching.

Thanks Garnett...40D shooter here, and as soon as the clouds part, I'll be doing this test and posting results.

@GarnettLeary

6 жыл бұрын

I love the 40D. Great H-a response native. Great and clear skies.

@GarnettLeary

2 жыл бұрын

40D is known for high native h-a transmission. I don’t know about the 5D III but it does have the advantage of being full frame. That sensor is superior to the others in light sensitivity. That 400 is an XTi? I think it’s the same camera. That one has the reciprocal screen. That’s extremely useful. Ultimately I’d pick the best microns per telescope.

great explaination man. I'm pretty new to cameras and i'm in love with astrophotography and this made it simple to understand the perfect setup. Nice!

@GarnettLeary

6 жыл бұрын

Thank you for the kind words. I wish you lots of luck. Clear skies.

Thanks for the information! I will be very helpful once I get a camera for my telescope

@GarnettLeary

4 жыл бұрын

Thank you for watching. I hope you get it soon and stick with it. Clear skies.

I had read / seen this subject before from a different source and I did the test. However - the other site didn't make it clear most of the details you included here. I don't recall them saying to make ISO setting differences a full stop - to adjust exposure compensation +/- 1,2,3 for the different ISO settings etc - nor did they say make an odd number of shots. With THEIR suggestions my GH3 gave good noise results at ISO 640. But I didn't get much light even at 30" exposures with more than 50 or so shots. I can hardly wait for the rain to quit so I can redo the test following your examples. Once I get to redo the test I'll post the results for my GH3. Thanks for clarifying the details on how to do this test correctly.

@GarnettLeary

6 жыл бұрын

You’re welcome. Glad it was useful. Please post your results for others so they will have a basis for the GH3. Clear skies.

Hello garnett, thank you very much for your very interesting and easy to understand video. it's serious, without show, it's about the thing. very sympathic. best regards from Germany , Erich

@GarnettLeary

2 жыл бұрын

Thank you so much and same to you.

@erichfurtwangler9683

2 жыл бұрын

@@GarnettLeary 😉

Thanks for the channel mention Garnett! Another very informative video as always.

@GarnettLeary

6 жыл бұрын

Thank you. I love your work. You may get a message from Fred L. He’s interested in learning your techniques.

@BayouCityAstronomy

6 жыл бұрын

Garnett Leary I'll always talk with anyone that wants to know about my videos. Thanks!

Hi Garnett. Good post. I will try this on my 60D, as soon as the temperature outside will aloud. Thanks.

@GarnettLeary

6 жыл бұрын

Awesome. I wish I still had mine. I love that model camera. Canon will release a D90 soon. :0

iso 200 is more noisy because you gave +3 exposure compansation! I think such test would be more reasonable when compansation is done just according to the exposure times, like 20 seconds for iso 200, 10 seconds for iso 400, etc...

Aren't you just comparing an underexposed image @ -3EV/200ISO to a properly exposed image @ ISO1600 and increasing the exposure in post? That in itself will introduce a lot of noise. I'd like to see a properly exposed image at each ISO and then compare. But with astrophotography the shutter time is the limiting factor. I'm wondering if a tracker with a lower ISO is the way to go? I just got the 6D and have not been blown away just yet.

@GarnettLeary

6 жыл бұрын

That’s a great question but the concern is image stretching for astrophotography. Concerning ISO you can actually shoot way too low even in a longer tracked exposure. ISO is more about light amplification than sensitivity. That’s a huge misconception. There are many objects in space that simply will not resolve with too low an amplification. Ultimately astro is the best way to test optics. You really find the faults in all equipment when putting it to a star test. For more detailed information on ISO try Lonelyspec. He has some great videos about the topic. I truly believe ISO is the biggest misunderstood aspect of night photography. Good luck and clear skies.

@Daniel_S.

6 жыл бұрын

The problem is-with different exposure times set on the camera, you will get different shot noise/photon noise in each picture. So the pictures aren't comparable anymore. The exposure time has to be the same in each picture. Ok, that was the one thing... Another problem is the difference in smoothing out details in camera between the iso steps. So you can't say by simply looking at the picture how much noise exactly is in the picture. You have to use statistical algoryhtms which you can find in some astrophoto stacking software to really get sure which is the best iso setting for your camera.

@RimantasLiubertas

6 жыл бұрын

There is a thing called ISO invariance. Basically you should get the same amount of noise no matter if you underexpose with a low ISO and then bring exposure up in post, or shoot at the proper ISO to start with. However not all cameras show ISO invariance, and Canon was not known for it. so I am not sure if it applies in this case.

Very interesting video, I have the 6D MII, I normally shoot ISO 400 but moved to 3200 for the optolong l-enhance. I may have to use 1600 from now on!

@GarnettLeary

4 жыл бұрын

I’m considering that model especially for its flip screen. Low light performance ratings are very close but you have a lot more bells and whistles, esp in video. Nice camera.

@johnnyredfireastroimaging5266

4 жыл бұрын

Garnett Leary I love it for video making. It does OK for Astro. I will actually consider a mirrorless camera next for taking astrophotography such as the Canon Ra

Shit was funny, spit my coffee up, Eugene from walking dead lmao, also 10+ points for playing Creedence, Good Vid!

@GarnettLeary

5 жыл бұрын

Thank you. Made it worth it. Creedence credit goes to my friends channel tho.

Great info m8, I did not know that :). was always thinkin that lower iso = less noise, hmm, I got some testing to do.

@GarnettLeary

6 жыл бұрын

Please post your model camera and results. I’m hoping folks use the comments section so folks can everyones results.

Please post your model camera and results for others to see. Let’s make this a useful thread. Clear skies.

very informative video! Thanks!

What are your thoughts on redoing the test but keeping the exposure balance on zero for all of the exposures? Would that not be a more accurate method?

@GarnettLeary

2 жыл бұрын

It can be done that way but it’s extremely difficult to determine the noise level of underexposed samples. The idea here is that a pre-determined “correct exposure” is known and every shot is to be placed there. It would be awesome if there were a program that can give an immediate interpretation in percentage of amount of noise perceived. I’d love to have that software.

@AB-ft2lb

2 жыл бұрын

@@GarnettLeary thanks, I'm going to do a bit more research on it. Your drift alignment video is brilliant btw, keep up the great work!

@GarnettLeary

2 жыл бұрын

Thank you. This is a great article: www.lonelyspeck.com/how-to-find-the-best-iso-for-astrophotography-dynamic-range-and-noise/

@AB-ft2lb

2 жыл бұрын

@@GarnettLeary Thanks, I conducted the test last night with 7 x 60s exposures through a telescope. The results were very similar in all exposures but ISO 800 which was set at EV0 was the best. I'm wondering if I re-do the experiment with ISO 6400 at EV0, which would make ISO 800 EV -2 how it would all turn out. I have a feeling ISO 800 will not be the smoothest second time around. If high ISO isn't necessarily noisier. How does it explain the High ISO Noise Reduction setting in cameras?

@GarnettLeary

2 жыл бұрын

High ISO noise reduction counters apparent noise from high signal amplification. Long exposure noise reduction is designed with the intent of removing amp noise. The former is always there whereas the latter is introduced through exposure time. I know in theory it sounds like amplified signal increases noise but it’s not that simple. It makes it more apparent. One could easily ask what’s the difference and most couldn’t tell you, the difference is “or is not” in a specific range. The idea behind ISO invariance test is to create identical exposures across varied ISO to locate the point of diminishing returns. Some sensors are truly invariant. Meaning 800 or 1600 doesn’t matter. A correct exposure is always a correct exposure. How you arrive at it changes. With a lower ISO and longer shutter speed or the inverse of a higher ISO and shorter exposure. Arguably one can immediately claim the lower ISO to be less noisy. In some cases it is. With an invariant sensor it would be identical with all settings equal. Let’s say the lower ISO shot was slightly underexposed and the higher slightly over. Assume no clipping or crushing occurred. If you push the lower expo up or bring the over down… the resulting grain would be consistent and the resulting image identical. Many sensors exhibit this behavior across a range of varied ISO’s or gain. They will have severe artifacts from too low, a moderate range where the signal climbs in relation to fairly flat signal noise and then a steep fall off at a point of diminishing returns at too high an ISO. You have to discover what that curve is or if it exists at all. Most will have a peak. With astro cameras they conveniently display that info as quantum efficiency. Most every dslr has ISO settings that exceed what is useful. The key ISO is the one that amplifies the signal most before increasing signal noise exponentially in relation. Additionally I have found that the performance numbers vary across cameras. One could expect similar results to what’s published assuming both the ambient temperature and age of the sensor were the same. It’s not written in stone but my older cameras seem not to handle higher ISO as well after they get aged. I don’t know much about deterioration of sensors beyond hot pixels but it has been my experience. The only way I know to run the test is as I have. All things equal and a decided +/- equivalent to range. You can measure the good signal to the unwanted. Too low and it’s too noisy. Too high and it’s typically past the point of diminishing returns.