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Old 18-07-2019, 09:08 AM
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Sony a7R IV, 61 Megapixel FF sensor released

Sony has just released the Sony a7R IV mirrorless Full Frame camera with 61 Megapixel sensor (9504 x 6336 pixels)

https://www.dpreview.com/news/774750...roduces-a7r-iv

and...
https://www.dpreview.com/articles/39...u-need-to-know

and Specs:
https://www.dpreview.com/products/so...specifications

Best
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Old 20-07-2019, 08:49 PM
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Yes this is what I predicted they would release. QHY somehow seemed to get their hands on this sensor and are about to sell a OSC cooled camera with this sensor.

How much better it would be than a straight A7riv I suppose is up for debate.

As far as noise goes, longer exposures and stacking handles that.

As far as potential star eater goes, hopefully Sony has improved their algorithim as they seem to have with A7riii and A7iii models. But would it be good enough for serious deep sky? No doubt there will be many threads about it within a few months when its in the hands of enthusiasts.

16 image pixel shift could be useful on a tracked scope as it means full colour on every pixel so similar in a way to filtered imaging which is usually one of the weaknesses of Bayer imaging - only 1 in 4 gets a particular colour (except green which gets 2 in 4). A7riii already does 4 image pixel shift which I have found to give better colour depth and also reduce noise.

Not needing a computer, small light and portable plus you can use it for other types of photography. Plus it will be less than half the price of the QHY model.

A7riv will have super low read noise as does the A7rii and A7riii as well as the A7iii.


Greg.
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Old 20-07-2019, 09:25 PM
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The QHY version is not cheap. $US8k...

Also I am not convinced (after having tinkered with QHY183 BSI CMOS OSC camera) the well depth is adequate.

After having just returned from Parkes, with a few people commenting on how good the dynamic range of these (and similar) sensors was/is....I am so far mystified on how to put theory in to practice.

My results to date have been good...but saturated stars with bugger-all faint data I am finding to be a challenge.

I'm happy to admit, it might be a learning curve on my part...but so far I have not managed to crack the code.
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Old 21-07-2019, 05:22 AM
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Originally Posted by Peter Ward View Post
The QHY version is not cheap. $US8k...

Also I am not convinced (after having tinkered with QHY183 BSI CMOS OSC camera) the well depth is adequate.

After having just returned from Parkes, with a few people commenting on how good the dynamic range of these (and similar) sensors was/is....I am so far mystified on how to put theory in to practice.

My results to date have been good...but saturated stars with bugger-all faint data I am finding to be a challenge.

I'm happy to admit, it might be a learning curve on my part...but so far I have not managed to crack the code.
Hey Peter.,
Looking at the specs whilst the 183mc has plenty of pixels and sensitivity, it's well depth
,and dynamic range does not look that good at unity gain. I went the other way with the 294MC with bigger pixels. Just depends on the FL. At unity gain it retains a lot more well depth than 183, more than 3X, a half stop more DR and better read noise. As you know, horses for courses. Recommend a filter like L-Pro or L-eNhance filters, it might help. You are welcome try out mine.
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Old 21-07-2019, 06:35 AM
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Quote:
Originally Posted by Peter Ward View Post
The QHY version is not cheap. $US8k...

Also I am not convinced (after having tinkered with QHY183 BSI CMOS OSC camera) the well depth is adequate.

After having just returned from Parkes, with a few people commenting on how good the dynamic range of these (and similar) sensors was/is....I am so far mystified on how to put theory in to practice.

My results to date have been good...but saturated stars with bugger-all faint data I am finding to be a challenge.

I'm happy to admit, it might be a learning curve on my part...but so far I have not managed to crack the code.
That 183 camera has a micro 4/3rds 20mp BSI sensor. BSI also increases well depth but its still a very small sensor. Around the size of the 8300 sensor or perhaps a bit smaller.

The full frame sensors would perform better. They have quite good well depth, extremely low read noise.

US$8K is around AUD$13K landed which is a lot for a OSC camera when the mirrorless camera with the same sensor is going to be under AUD$5K.
How valuable is the cooling? It gets rid of the star eater but also loses pixel shift tech and compactness/portability and no need for a computer.

I think there is little doubt that the A7rii, iii and iv sensors are cutting edge tech and the best out there in CMOS land.

Greg.
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Old 21-07-2019, 06:21 PM
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This camera/sensor should be quite illuminating on the optical quality of our favourite scopes and lenses

It’ll be interesting to see what the well depth turns out to be, given they’ve equipped it with a 16-bit ADC.

Only problem I see with the Sony body for astro is (a) OSC and (b) status of star eater/spatial filtering. Personally, I’d rather have the raw data warts and all...
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Old 22-07-2019, 06:04 PM
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Originally Posted by Camelopardalis View Post
This camera/sensor should be quite illuminating on the optical quality of our favourite scopes and lenses

Itíll be interesting to see what the well depth turns out to be, given theyíve equipped it with a 16-bit ADC.

Only problem I see with the Sony body for astro is (a) OSC and (b) status of star eater/spatial filtering. Personally, Iíd rather have the raw data warts and all...
I agree with you. Not sure what you mean by well depth and the 16bit ADC. Well depth on a BSI sensor is much larger because the 40% of surface area that a typical CMOS sensor loses to the surrounding circuitry is gained for the sensor.

I thought 16bit ADC were not uncommon. I am pretty sure Fuji X cameras have had 16bit down to 14 bit output for some time.

Well depth on the A7rii and A7riii which are similar sensors is quite high despite smallish pixels.

Its more the filtering that may be an issue. I can see the typical Sony wormy type noise reduction in a few sample images so don't expect much change there.


Greg.
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Old 22-07-2019, 08:21 PM
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What I was getting at was that I believe this is the first mainstream CMOS sensor with a 16-bit ADC. The Fujis only kick out 14-bit raw files. I suspect the GFX series would be different.
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Old 26-07-2019, 08:01 PM
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Originally Posted by Camelopardalis View Post
What I was getting at was that I believe this is the first mainstream CMOS sensor with a 16-bit ADC. The Fujis only kick out 14-bit raw files. I suspect the GFX series would be different.
The 16 bit DAC means nothing unless the well depth/read noise is supported 16 bits of actual data. Otherwise you are simply dividing useless noise into smaller chunks.
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Old 26-07-2019, 08:57 PM
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The 16 bit DAC means nothing unless the well depth/read noise is supported 16 bits of actual data. Otherwise you are simply dividing useless noise into smaller chunks.
Which was exactly my point...they must believe it is capable of >14 bits of dynamic range to go to the effort of equipping it with a 16-bit ADC.

Their previous sensors have been approaching 14-bit DR. We just donít know the juicy details at this point.
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Old 14-08-2019, 06:59 AM
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Which was exactly my point...they must believe it is capable of >14 bits of dynamic range to go to the effort of equipping it with a 16-bit ADC.

Their previous sensors have been approaching 14-bit DR. We just don’t know the juicy details at this point.
It does 15 stops of dynamic range but only when downsampled to 8 bits.

I imagine normal use dynamic range is similar to the previous A7riii and ii at around 14.7 stops.


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Old 14-08-2019, 10:09 PM
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The QHY version is not cheap. $US8k...

Looks like some of the QHY dealers are now offering the QHY600 for sale at $US5K . (introductory price)

https://www.astrofactors.com/shop/co...40-qhy600.html
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Old 15-08-2019, 06:30 PM
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Still $8,500 or so. Compares with AUD$5,400 for an A7riv.

But its cooled and no spatial filtering of the RAWs. Is it worth it though?

You also get pixel shift and an intervalometer etc with the mirrorless and no need for a computer.

Greg.
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Old 16-08-2019, 08:44 PM
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I whinged to ZWO ASI about the discontinuation of the ASI094 yesterday (it was on my shortlist of cameras), and they replied:
es, ASI094 camera is discontinued. We are developing ASI6200 camera which meets your requirement (see specification below).
62 mega pixel full frame
Pixel Size:3.76um
Sensor Size: 36mmx24mm
Resolution: 9600x6300
16bit ADC
IMX455
It will be available in December. We will make updates on our website once ready.

So, not long to wait,. I think I'll hold off getting the QHY367C and wait for this beasty, though the price is daunting....Imagine the file sizes and the buffering demands.
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Old 29-08-2019, 10:35 AM
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I'd wait and see sample images. It most likely will be noisier. 61mp is not all roses, it means very small pixels and more noise.

Greg.
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Old 29-08-2019, 08:46 PM
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I’ll reserve judgement until they hit the market. There are some pretty capable sensors on the market with pixels under 5 microns, and they don’t demonstrate 14.7 stops of dynamic range...

What it will show is how good a given scope’s imaging circle is. Some folk with too much invested in this game might not like to know
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Old 30-08-2019, 06:52 AM
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Originally Posted by Camelopardalis View Post
Iíll reserve judgement until they hit the market. There are some pretty capable sensors on the market with pixels under 5 microns, and they donít demonstrate 14.7 stops of dynamic range...

What it will show is how good a given scopeís imaging circle is. Some folk with too much invested in this game might not like to know
Gordon Laing posted a video review with night photos with a side by side A7riii image to compare. The A7riv was quite noticeably worse. But still useable, I mean we are talking about less than the class leading sensor. A7riv is probably closer to Canon level of noise.

The Sony claim of 15 stops of dynamic range is also bogus. That is only downsampled to 8mp and 12 bits. An unlikely use of a sensor like this.

Dynamic range is a bit worse low down and a bit better higher up in the ISO. Interestingly it now has dual gain that kicks in at ISO320 versus 640 with the A7riii. I would prefer ISO640 as its a more useable ISO level for imaging.

https://www.dpreview.com/forums/post/63031042?image=1

Greg.

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Old 30-08-2019, 05:51 PM
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Interesting read, thanks Greg

Certainly not getting something for nothing any more.
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Old 17-09-2019, 04:28 AM
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I have the A7M3, and this new camera isn't on my radar. I did note however a report that it has the "star eating" issue like the A7RM3 has/had, "except the behavior starts at 3.2 secs instead of 4 seconds (on the A7RM3)".
Something to consider.
Gary
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Old 17-09-2019, 09:04 AM
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Yes I read that test from Jim Kasson on DPReview Sony full frame forum:

https://www.dpreview.com/forums/post/63099143

Also the high ISO tests show its a bit more noisy than the A7riii at higher ISOs.

Plus it has less dynamic range than the A7riii.

So for astro I see little reason to use it. it does not have any proper long exposure facility like Canon and a weak intervalometer that is only half featured.

16X pixel shift may be useful but mainly only in the fact that one click gets you 16 images so that would be a good stack. But again max exposure is 30 seconds.

Sony is simply not into providing astro type features.

Canon EOS R is ahead here in my opinion. The 30mp sensor is plenty sharp, is quite low noise (a tad noisier than the Sony) has accurate star colours and no funny RAW filtering. It also has long exposure ability longer than 30 seconds. It lacks an incamera intervalometer.
Variangle screen versus Sony tilt screen for me is no real gain as the variangle does not like L brackets. So it requires a special L bracket which are only now on the market.

EOS R touch screen is like a smartphone and nice to use. Sony does not have a proper touch screen only for autofocus point. So they are very behind there.

IBIS is not something you use in nightscapes.
Neither is dual card slots. Pixel shift (4 images) is workable with a tracker on the Sony's and is worth having.

Canon are rumoured to be releasing a high MP EOS RX later this year. Perhaps 83mp?
I imagine it will be somewhat noisy for nightscapes unless they have made some breakthroughs in their sensors which are good but old fashioned.


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