Just got a Sony A7iv. Went out tonight to compare it to my older A7Rii. Tried to induce star eater in the A7Rii by shooting for 6 seconds in e-shutter mode. Then compare it to mechanical shutter and continuous-shot mode where the star eater filter doesn't work. For whatever reason, it's no longer easy to see any difference. I believe Sony kind of fixed it with firmware version 4.01. I did notice what looked like hot pixels in the continuous mode that were not there for the plain e-shutter mode. So, noise reduction still takes place, but it's more subtle only taking out the 1 or 2 pixel bright spots. I then compared to the A7iv. It wasn't seeing the "hot" pixels the A7rii had in mechanical shutter continuous mode. So...they were hot pixels and not stars. What's still kind of an issue is the faint stars tend to be greenish. So, I think Sony is still messing with their noise reduction on the tiny stars.
It really depends on what you want to do with it. The truth is I never used the a7riv, but if I had to choose one today, I would go with the a7iv for general nightscapes. It's a newer model with more features and a 33mp sensor, which is more than enough. Remember you will have to deal with huge files with the 60mp sensor. So slower transfer and post processing. The only reason to choose the R series is if you want to capture high-resolution files to print, etc, but still you can just use the a7iv and capture mosaics so you get more resolution.
Just got a Sony A7iv. Went out tonight to compare it to my older A7Rii. Tried to induce star eater in the A7Rii by shooting for 6 seconds in e-shutter mode. Then compare it to mechanical shutter and continuous-shot mode where the star eater filter doesn't work. For whatever reason, it's no longer easy to see any difference. I believe Sony kind of fixed it with firmware version 4.01. I did notice what looked like hot pixels in the continuous mode that were not there for the plain e-shutter mode. So, noise reduction still takes place, but it's more subtle only taking out the 1 or 2 pixel bright spots. I then compared to the A7iv. It wasn't seeing the "hot" pixels the A7rii had in mechanical shutter continuous mode. So...they were hot pixels and not stars. What's still kind of an issue is the faint stars tend to be greenish. So, I think Sony is still messing with their noise reduction on the tiny stars.
For astrophotography can you recommend between alpha 7-4 or 7R4?
It really depends on what you want to do with it. The truth is I never used the a7riv, but if I had to choose one today, I would go with the a7iv for general nightscapes. It's a newer model with more features and a 33mp sensor, which is more than enough. Remember you will have to deal with huge files with the 60mp sensor. So slower transfer and post processing. The only reason to choose the R series is if you want to capture high-resolution files to print, etc, but still you can just use the a7iv and capture mosaics so you get more resolution.
@ thank you, useful!