Sony a7iv feedback

cyvideo

cyvideo

Veteran
Happy to confirm that I've just had an a7iv shooting 4k 50p crop 422 10-bit XAVC-S running for three hours twenty-two minutes without a hitch as a locked off wide camera on a live stage show in a 72-degree temp theatre. Locked the iris and set Auto ISO to 125-1600 and recorded in S-Cinetone. Set the auto exposure to -1.3 EV and it handled the lighting highs and lows remarkably well.
Ran the supplied charger unit connected via the USB C port for the exercise. At the end of it all when the USB power was disconnected the battery was showing 53% charge. More than happy with the video out of it on this first test. I will check out the harsh Aussie sun and some night stuff when given the opportunity.

Chris Young
 
hey Chris, what crop factor can you achieve with the a7iv when recording 4K with clear image zoom? can you crop all the way up to 2x, like a m43 sensor size? but I imagine you only get eye AF and other fancy AF modes in APS-C crop, and not when using clear image zoom? Thanks
 
Mr. A.

No 2 x 4k in Clear Image. It's 1.5 x only. 2 x is available in HD mode. In the normal "crop" in HD or 4K mode all your face, eye, touch and tracking work in every respect. In Clear Image mode, you get a dotted outline box indicating the AF boundaries imposed when in Clear Image mode. This box outline covers about 80% of the sensor coverage. No touch or tracking AF is available in Clear Image. Though the speed and accuracy of the AF in the Clear Image mode is looking quite satisfactory in most of the scenarios I've conjured so far for testing. That's testing with some of the current range of Sony and Tamron lenses that I can put my hands on. For production work, I'm mainly using zooms so the CI has limited application at the moment. Though I have used CI on the little Z90 where again it was 2 x in HD and 1.5 x in 4K where it was very good... surprisingly good! It also works well on the Z280 so I think I can see uses for it on this a7iv if it delivers results like the Z90 and Z280.

Chris Young

As an aside. Interestingly using crop mode in 4K with CI at 1.4x allows me to use MTF's optical B4 to E-Mount adapter with a decent B4 lens. I've tried it indoors testing with a Fujinon 7.6 x 18 2/3" lens and can shoot 50/60p 4K without any apparent technical downsides. I will try to do some serious tests with this because 4K 50/60p with an 18-22 x B4 zoom has a certain appeal for some jobs. Initially, I was specifically testing for my pet hate which is CA and on the limited testing done so far with the MTF with its 7 element relay lens and a decent B4 I'm quite impressed. The MTF's optics are specifically designed to re-converge a B4 lens' beam focusing to work with single-sensor cameras as opposed to the three sensor prism-based cameras that B4s were originally designed to work with.

Just got to find the time and motivation to get out there and do it!
 
Thanks Chris -

Am I to understand that you can record 4K, enter APS-C crop mode and THEN further magnify 1.5x if you engage CI from there? Am I mistaken in thinking that you could get a 1.5x crop on the 1.5x crop? So, 2.25 crop? Or can you not use clear image zoom when you're in APS-C crop mode?

The a7iv has a 7008-pixel wide sensor. So I would think that you could get down to a 1.825 horizontal crop and still get 3840 pixels wide with no interpolation or up-rezzing necessary.

I'm interested in getting a 400mm-equivalent (or close to it) from my tamron 70-180 in 4k60p.

Best,
Abe Halpert
 
It's working like this. Selecting crop mode gives you, to be accurate based on the following figures, APS-C (Sony) (23.6 x 15.6 mm) (1.53x crop). So a crop factor of 1.5 in round figures. When in crop mode you can then by using Clear Image zoom push in another 1.5 x in 4K. In HD mode in APS-C crop, it will allow Clear Image to push in up to 2x. The a7iv in crop mode has a rolling shutter figure of 13ms.

Crop mode on the a7iv is effectively 14.5 Megapixels with approx 4672 x 3112 pixels. Hence Sony's claim of the a7iv's crop mode being down-sampled from 4.6K. When shooting stills in APSC crop mode you get an indication at the top of the viewfinder that says 14M.

To put all that in context with some of Sony's other models you can look at the following:

A7S iii FF sensor

Sensor FF 35.6 x 23.8 mm (Full-Frame) Diagonal = 42.82mm
Sensor Resolution Actual: 12.9 Megapixel
Pixel dimensions 4240 x 2832
Effective: 12.0 Megapixel
Rolling shutter 8.7ms

And for comparison to one of the most recent popular top-selling S35 cameras. Sony's PXW-FS7:

Sensor S35 23.6 x 13.3 mm (S35) Diagonal = 27.09mm
S35 resolution actual: 11.6 Megapixel
Pixel dimensions 4096 x 2160
Effective 8.8 Megapixels
Rolling shutter 14ms

So the a7iv performance-wise in crop mode is close to an FS7 but is delivering a higher res image as it is down-sampling from 4.6K as opposed to the FS7 which delivers an actual crop of 4096 from its S35 sensor. This is why I hung out for the a7iv (hoping for 422 10-bit) as it meant I can use my manual S35 and APS-C lenses on both the FS7 and the a7iv. It also means I can use my FF manual lenses with a Speed Booster in crop mode. This as you would know makes a FF F/1.4 into a crazy F/1.0 with its added F stop. Which is crazy fast on a modern hi-res lower noise sensor.

Chris Young
 
If anyone is interested I managed to get outdoors for the first time with the A7iv. The afternoon was one of those nasty hi dynamic range hi-glare heavy cloud cover days. Lots of white surfaces pointing skywards where detail needed to be retained. The a7iv seemed to handle the day's dynamic range pretty well which just makes exposing so much easier. This was shot in XAVC-S 4K 422 50p using PP11 S-Cinetone and ISOs between 125, 160 and 200. I also used a Freewell 1-5 stop VND. I found to get the safest exposures out of the S-Cinetone was to keep my maximum highlights at or around 90 IRE. This meant any exposure excursions that went past that point were on the whole looking pretty natural. Because of the distances involved, I used Tamron's 18-300mm F/3.5-6.3 Di III-A VC VXD. The thing that amazes me with this lens is at no time did I see any CA issues on high contrast edges. The other thing you will notice is this lens exhibits virtually no breathing. Check the tap focus pulls from the wharf to the boat and back at around the two minute mark.

Chris Young

 
I think you'll find it quite forgiving to work with. So far so good. Need to try it out on a, as we used to call it when shooting film "a soot and whitewash day". Extreme sun and harsh deep shadows as that will ask the camera some serious dynamic range questions. Will try S-Cinetone and S-LOG. Once I know its limits then I'll feel happier at committing it to a paying job.

Chris Young
 
cyvideo said:
I think you'll find it quite forgiving to work with. So far so good. Need to try it out on a, as we used to call it when shooting film "a soot and whitewash day". Extreme sun and harsh deep shadows as that will ask the camera some serious dynamic range questions. Will try S-Cinetone and S-LOG. Once I know its limits then I'll feel happier at committing it to a paying job.

Chris Young
Click to expand...

One of the things that I like about the A7IV & A7sIII compared to the Canon models is the 10bit color profiles. I hope to be able to dial in some profiles where I can not have to use LOG all of the time. I am tired of "taking the gray out...".
 
Bassman2003 said:
One of the things that I like about the A7IV & A7sIII compared to the Canon models is the 10bit color profiles. I hope to be able to dial in some profiles where I can not have to use LOG all of the time. I am tired of "taking the gray out...".
Click to expand...

This is exactly what I am finding with this a7iv and S-Cinetone... so far! Hence the working out how far it can go without having to "LOG" it. CineD is quoting that their IMATEST results confirm that the camera has a pretty decent dynamic range, showing 12.9 stops at SNR = 2 and 14 stops at SNR = 1:

https://www.cined.com/sony-a7-iv-lab-test-rolling-shutter-dynamic-range-and-latitude/

For a $2,500 camera you can't argue you are not getting value for money with that kind of performance. As you say, to be able to work in 10-bit 422 with a reasonable bit depth and have the ability to be able to push a "ready-rolled" codec like S-Cinetone quite hard is quite liberating after having had to work with S-LOG3 to get that sort of flexibility. S-Cinetone isn't S-LOG but it's definitely second best as an onboard codec on these Sony cams and will definitely allow me to use S-Cinetone on some jobs where 709 wouldn't cut it which basically pushed you into the LOG domain. Work commitments have finished for me for the year so hopefully, I'll get a bit of time to give this little Alpha a few more runs under different conditions before the silly season starts. Everyone have a good Xmas break.

Chris Young
 
You Too. Thanks for sharing and I am sure I will be posting when I get my Alpha's up and running. I enjoy the "standard" color profile color rendition from watching YT videos as well.
 
Another update. Had a chance last night with the a7iv to go up a street in our neighbourhood that goes crazy with Christmas lights. Extreme highlights and extremely dark areas. How would S-Cinetone at various ISO settings handle these mixed lighting ranges? Could I mix a wide range of ISO settings without having to resort to a lot on NR in post. Reasonably happy with the results. Again XAVC-S 4K 422 50p with a pretty s-l-o-w lens! No NR applied to any clips.

Chris Young.

EDIT: This is the HD downconversion of the 4K video. The 4K link is now included below.


4K version

 
Last edited:
I guess I should have been more specific. Like "No NR applied externally". Whatever NR is applied in-camera is obviously not user-accessible. However Sony is managing the NR in the a7iv it doesn't look overly aggressive as the sharpness and detail retention in the images looks to be well balanced across the ISO levels with reference to overall image noise.

Chris Young
 
How far would you feel comfortable raising the ISO, Chris? And how do you think its high-iso performance compares to other sony cameras? Thank you
 
Base on what you posted and what I've seen and heard reviews say, for the most part the image quality and low light performance is very similar to the A73. There are a lot of usability things like flip screen and full size HDMI port, 10bit, 4k 60p, better AF, new menu, etc which are valuable but there is nothing that will jump out in the footage and grab you.
 
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