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Sony a7 IV Lab Take a look at – Rolling Shutter, Dynamic Vary and Latitude


Sony a7 IV Lab Test - Rolling Shutter, Dynamic Range and Latitude

The Sony a7 IV is quickly to be launched. A manufacturing mannequin is already on our desk, so we seized the chance to “torture” it in our lab – no mercy as regular! And for the file, it didn’t disappoint us. to listen to extra? Right here is our Sony a7IV lab check.

As a few of you may need learn in earlier posts of mine, I owned a Sony a7S II for fairly a number of years, and in addition borrowed the seize & go cam from CineD, a Sony a7 III fairly incessantly as a B cam. So at any time when I can get my palms on a brand new Sony Alpha cam, I’m fairly excited!

Again then the Sony a7 III felt like the proper center floor of the Sony Alpha collection cameras when it comes to worth/efficiency ratio. So will the Sony a7 IV once more match into this position? Let’s have a more in-depth have a look at how the lab testing performs out …

The Sony a7 IV within the lab with a Zeiss 85mm T1.5 Compact Prime. Picture credit score: CineD

Rolling Shutter of the Sony a7 IV

Utilizing our commonplace strobe mild reveals a rolling shutter worth of 26.8ms operating the Sony a7 IV in 4K full-frame mode:

Sony a7 IV, full-frame mode, rolling shutter measurement. Picture credit score: CineD

Ouch – this can be a reasonably excessive worth (decrease values are higher)! For comparability, the Sony A1 in 8K full-frame mode reveals 16.6ms, the Sony a7S III solely 8.7ms (Lab checks right here and right here)! Additionally, the competitors fares higher e.g. with the Panasonic LUMIX S1 and LUMIX S5 round 22ms (lab checks right here and right here) or the Canon EOS R5 at 15.5ms (17:9, lab check right here). Solely the Canon EOS R6 is worse with 30.6ms (lab check right here).

In APS-C crop mode, the rolling shutter in UHD turns into fairly a bit higher at 13ms.

Sony a7 IV – Dynamic Vary at ISO800, SGamut.Cine/SLog3

If you’re concerned about our process and studying how we check dynamic vary, please head over right here.

The Sony a7 IV encompasses a 33-megapixel sensor, however solely permits video recording at 3840×2160 UHD full-frame mode as the utmost decision and that’s the place Dynamic Vary outcomes get attention-grabbing.

Sony claims on its webpage that the digital camera downsamples UHD from the total 7K sensor – therefore the picture ought to present reasonably good dynamic vary outcomes as downscaling reduces noise therefore enhancing the signal-to-noise ratio (SNR).

Wanting on the waveform of our Xyla 21 stepchart, we see about 13 stops above the noise ground:

Sony a7 IV in SG3.C/SLog3 at ISO 800 Waveform plot, Xyla 21 stepchart. Picture credit score: CineD

The noise ground appears very clear, however not overly processed by inner noise discount just like the Sony a7S III reveals. Talking of inner noise discount, this can’t be turned off sadly as regular with Sony Alpha cameras.

IMATEST confirms this, exhibiting 12.9 stops at SNR = 2 and 14 stops at SNR = 1:

Sony a7 IV- IMATEST Dynamic Vary outcome. Picture credit score: CineD

By the best way, a really comparable result’s obtained from the Sony A1 if the 3840×2160 full-frame mode is chosen – additionally right here the sensor is correctly downsampled.

I’m impressed! These are actually good outcomes from the Sony a7 IV! Simply bear in mind, a lot of it’s achieved by downsampling and important noise discount in digital camera which can’t be turned off. In the event you have a look at the IMATEST outcome, within the center graph above the blue SNR = 1 line designated with “14” you may see about 1 further cease earlier than the sign differentiation is gone. In the event you examine that with our benchmark for dynamic vary, the ARRI ALEXA LF (lab check right here) you may see in the exact same IMATEST graph above the blue “14.7” line (14.7 stops for SNR = 1) some further 3 stops. These could be accessible through the use of noise discount in put up with the ARRI digital camera. Therefore, the Sony a7 IV has in complete about 3 stops much less dynamic vary than the ARRI ALEXA LF. That is additionally confirmed by the latitude checks under.

Latitude Take a look at with the Sony a7 IV

Latitude is the aptitude of a digital camera to retain colours and element when over or underexposed. For our latitude check we’ve got a normal setup with fastened studio lights and a set distance between topic and lights, and topic and rear wall.

We begin to expose the digital camera at 1/25s shutter pace at T1.5 and regulate the studio mild such that the brow of my colleague Johnnie is on the cusp of clipping. From there we successively underexpose the scene by adjusting the iris of the Zeiss Compact Prime 85mm T1.5 from F1.4 to F2, F2,8, F4, F5.6, and F8, and from there onwards we regulate the shutter pace to 1/50s, 1/100s and1/200s. This manner we cowl a latitude of 8 stops.

To offer you a degree of reference, our base publicity scene within the studio displays a luma worth of about 60% (ungraded) at Johnnie’s brow.

The digital camera was once more set to ISO800, SGamut3.Cine / SLog3 and the codec used was XAVC S-I 4K (10bit 4:2:2).

CineD lab base publicity scene of the Sony a7 IV. Picture credit score: CineD

Now let’s see how the digital camera reacts to three stops overexposure, pushed again to our baseline:

Sony a7 IV three stops above our base publicity, pushed again. Picture credit score: CineD

Johnnie’s brow is on the cusp of clipping, a number of patches of the colour checker have been clipped already. Apparently, the picture is a bit blueish, cooler when in comparison with our base publicity.

Not a lot occurs once we successively underexpose our picture from 2 stops over to three stops beneath, pushed again to base publicity.

Now, at 4 stops underexposure, issues get attention-grabbing as swiftly fairly some luma & chroma noise begins to indicate up:

Sony a7 IV 4 stops beneath our base publicity, pushed again. Picture credit score: CineD

Additionally, the picture will get a slight pinkish tint this time. However nonetheless, all is nice. After all, you may additional cut back the noise in postproduction when you like:

Sony a7 IV 4 stops beneath, pushed again & noise discount added. Picture credit score: CineD

At 5 stops underexposure (from our base), swiftly heavy pinkish chroma noise is all throughout the picture:

Sony a7 IV 5 stops beneath our base publicity, pushed again. Picture credit score: CineD

The picture breaks down – we went too far, because the shadows are drowned in pink chroma noise which can’t be eliminated by noise discount:

Sony a7 IV 5 stops under base, pushed again and utilizing noise discount. Picture credit score: CineD

Utilizing temporal and spatial noise discount in DaVinci Resolve 17.4.1 with emphasis on chroma noise discount nonetheless can not save the picture, because the noise will not be finely distributed. It reveals bigger blotches of pink chroma noise as a substitute – take a look on the shadow facet of Johnnie’s face for instance. Normally, noise discount in postproduction with the Sony a7 IV is a dangerous enterprise, as these bigger blotches of noise flip into bigger, plasticky-looking monochrome areas. The remainder of the picture is OK – no horizontal or vertical stripes are seen, however I can not tolerate pink shadows, particularly on faces. Sorry.

Once more, an outdated Sony Alpha phenomenon has raised its ugly head: the mix of a weaker codec and inner noise discount (which can’t be turned off) results in these massive blotches of pink chroma noise, which can’t be eliminated successfully by the noise discount software in put up.

And that results in the same conclusion that we had for the Sony a7S III – round 7 stops of publicity latitude are doable. The Sony A1 was 1 cease higher in that regard – the pink shadows on Johnnie’s face confirmed up one cease later, at 6 stops of underexposure, pushed again to base.

Additionally, the Panasonic LUMIX S1, S5, and S1H are able to 8 stops of publicity latitude – the noise is finely dispersed, making it simpler to take away with noise discount in put up. Clearly, Panasonic has the higher picture processing pipeline right here.

And final however not least, simply to say the present benchmark, the ARRI ALEXA LF achieved 10 stops of publicity latitude in our commonplace studio scene (lab check right here).

Abstract

The Sony a7 IV reveals total very sturdy ends in the lab check – actually good dynamic vary, 12.9 stops at SNR = 2! Relatively good publicity latitude with 7 stops. However the rolling shutter falls a bit brief sadly, it’s on the excessive finish at 26.8ms, additionally compared to the Panasonic LUMIX S1, S5, and S1H, the Canon EOS R5, and the Sony A1 and a7S III full-frame cameras.

Are you contemplating the Sony a7 IV as a stable middle-ground full-frame digital camera? Have you ever shot with it already? If sure, inform us extra within the feedback part under.



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