The GetDPI Photography Forum

Great to see you here. Join our insightful photographic forum today and start tapping into a huge wealth of photographic knowledge. Completing our simple registration process will allow you to gain access to exclusive content, add your own topics and posts, share your work and connect with other members through your own private inbox! And don’t forget to say hi!

ALPHA A7R MARK IV - continuous RAW shooting

Ed Hurst

Well-known member
Hello all,

I have a question about the ALPHA A7R MARK IV. Assuming that I am shooting uncompressed RAWs in the format that produces the best quality, do you know what the shortest exposure time is that allows unlimited sequences of RAWs to be shot and written to the card? Assume a card fast enough not to be the bottleneck (so the speed bottleneck is the camera). I often shoot hundreds or thousands of consecutive files for star trails, so I am looking for the shutter speed at which the camera can do this continuously without stopping to clear the buffer. On my Pentax 645Z, I find it will shoot 2 second exposures like this without pausing at all - until the card is full. However, exposures shorter than 2 seconds cause the camera to pause from time to time while the processing/writing catches up with the writing to the card.

So what's the magic number for the ALPHA A7R MARK IV?

Obviously I am looking for an answer validated in practical experience if possible :)

Many thanks in advance...

Ed
 

pegelli

Well-known member
Hi Ed, my highest Sony is the A7Rii so unfortunately I can't test it for you. I hope somebody else can.

I don't know if you're aware and if it is influencing your decision to get an A7Riv, but with long exposures > 3.2 seconds a certain noise reduction algorithm kicks in that's also known as "the star eater" which sees some stars as noise and removes them. Since you are a star and star trail photographer this might impact how good this camera is for your use. Here's an article by Jim Kasson on this phenomena, but you can also google "Sony Star Eater" and you'll find many articles on it (as always on the internet some more useful than others, which is why I linked Jim's article because he really knows what he is talking about)

However if you're shooting sequences which are all exposures shorter than 3.2 seconds it might not be a problem.
 

Ed Hurst

Well-known member
Hi Ed, my highest Sony is the A7Rii so unfortunately I can't test it for you. I hope somebody else can.

I don't know if you're aware and if it is influencing your decision to get an A7Riv, but with long exposures > 3.2 seconds a certain noise reduction algorithm kicks in that's also known as "the star eater" which sees some stars as noise and removes them. Since you are a star and star trail photographer this might impact how good this camera is for your use. Here's an article by Jim Kasson on this phenomena, but you can also google "Sony Star Eater" and you'll find many articles on it (as always on the internet some more useful than others, which is why I linked Jim's article because he really knows what he is talking about)

However if you're shooting sequences which are all exposures shorter than 3.2 seconds it might not be a problem.
Thanks so much for sharing this vital information! Back to the drawing board, unless someone can tell me that the camera will shoot continuous uncompressed RAWs, without ever filling the buffer, if the exposure length is shorter than 3.2 seconds???
 

Ed Hurst

Well-known member
Ed, if you are looking for a new camera (and you are not leaving the Pentax MFD world) how about a Pentax K-1? The Astrotracer function might also be of interest for you. Adapting your 645 glass might be easy too.

https://www.lonelyspeck.com/pentax-k-1-mark-ii-astrophotography-review/

Just a thought. But as Pegelli pointed out,do some research on Sony's star-eater issue.
Thanks so much, Will. Yes, the K1ii does seem to have much to commend it - I am merely looking into the best temporary solution (perhaps involving renting) while my 645Z is off being repaired (which might take months!). I will be continuing with the 645Z as soon as I can. The star eater issue with Sony makes me think the best answer might be Pentax K1ii or Nikon D850... Pity - the Alpha A7Riv in many ways seems like an excellent option, but not if it's going to munch on stars :)
 

B L

Well-known member
I think Sony should take not of this thread highlighting shortcomings.
My point is, if Sony sensors are used in Pentax and Nikon also,does that mean the firmware/software algorithm is playing it part in Pentax for doing excellent in astrophotos. Can Sony not go back to review frimware/software and not be a star eater? It looks as bad as the blackhole !
 

pegelli

Well-known member
I think Sony should take not of this thread highlighting shortcomings.
My point is, if Sony sensors are used in Pentax and Nikon also,does that mean the firmware/software algorithm is playing it part in Pentax for doing excellent in astrophotos. Can Sony not go back to review frimware/software and not be a star eater? It looks as bad as the blackhole !
Fully agree, I know of at least two big internet petitions to try and convince Sony to fix this issue, still to no avail.

The issue doesn't impact me and the type of shooting I do, but it just seems so straight forward to fix it and increase the usefulness of these cameras that I don't understand why they don't fix it. A simple firmware update should do since the issue was also introduced for the first time with a firmware update on the A7Rii (if I'm not mistaken) a few years ago.
 

B L

Well-known member
Fully agree, I know of at least two big internet petitions to try and convince Sony to fix this issue, still to no avail.

The issue doesn't impact me and the type of shooting I do, but it just seems so straight forward to fix it and increase the usefulness of these cameras that I don't understand why they don't fix it. A simple firmware update should do since the issue was also introduced for the first time with a firmware update on the A7Rii (if I'm not mistaken) a few years ago.
I think Sony sjould borrow clever Pentax software writers. I think some of them could be astrophotographers knew how to overcome.
So kudos to Pentax. :clap:
 

tsjanik

Well-known member
Ed:
Will's suggestion of a K-1 is a good one. I have found the K-1 to be excellent. It's not the 645Z, but it does have PS mode which makes it competitive. I avoided the mark II version based on comments of decreased sharpness as a consequence of noise reduction (in RAW). The K-1 will allow you to use the same batteries as the Z, and, most importantly for me, the UI and ergonomics are superb and familiar. I got a Fuji 50r for the weight reduction and EFSC. It's an excellent camera, but after a year, I am still frustrated by the ergonomics, menus, EVF and inappropriate placement of buttons.

Tom
 
Top