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Sony a7 IV Lab Check – 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 report, it didn’t disappoint us. to listen to extra? Right here is our Sony a7IV lab check.

As a few of you might 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 every time I can get my arms 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 sequence cameras when it comes to worth/efficiency ratio. So will the Sony a7 IV once more match into this function? 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 normal strobe gentle 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 moderately 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 keen on our process and studying how we check dynamic vary, please head over right here.

The Sony a7 IV includes 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 fascinating.

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

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

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

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

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

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

By the best way, a really related 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 take into accout, a lot of it’s achieved by downsampling and vital noise discount in digicam which can’t be turned off. If you happen to have a look at the IMATEST consequence, 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. If you happen to evaluate 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 by utilizing noise discount in publish with the ARRI digicam. Therefore, the Sony a7 IV has in whole about 3 stops much less dynamic vary than the ARRI ALEXA LF. That is additionally confirmed by the latitude checks beneath.

Latitude Check with the Sony a7 IV

Latitude is the potential of a digicam to retain colours and element when over or underexposed. For our latitude check now we have a regular setup with fastened studio lights and a set distance between topic and lights, and topic and rear wall.

We begin to expose the digicam at 1/25s shutter velocity at T1.5 and alter the studio gentle 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 alter the shutter velocity 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 digicam 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 digicam 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 after 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 fascinating as rapidly fairly some luma & chroma noise begins to point out 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 sweet. In fact, you may additional scale back the noise in postproduction in the event you like:

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

At 5 stops underexposure (from our base), rapidly 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 beneath 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’t save the picture, because the noise will not be finely distributed. It reveals bigger blotches of pink chroma noise as an alternative – take a look on the shadow facet of Johnnie’s face for instance. Basically, 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’t tolerate pink shadows, particularly on faces. Sorry.

Once more, an previous Sony Alpha phenomenon has raised its ugly head: the mix of a weaker codec and inside noise discount (which can’t be turned off) results in these giant blotches of pink chroma noise, which can’t be eliminated successfully by the noise discount device in publish.

And that results in an analogous conclusion that we had for the Sony a7S III – round 7 stops of publicity latitude are potential. 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 publish. 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 normal studio scene (lab check right here).

Abstract

The Sony a7 IV reveals general 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 strong middle-ground full-frame digicam? Have you ever shot with it already? If sure, inform us extra within the feedback part beneath.



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