Sony has increased the number of autofocus points available from 25 on the A7S to 169 with the new camera. It also claims a 2x faster AF response in video mode. It still relies on contrast detection autofocus, however, and unlike the A7 II there's no phase detection element.

The Gamma settings include Sony's S-Log2 as well as the new S-log3 setting. These can increase dynamic range by up to 1300% by creating very flat looking footage that is ideal for post-capture grading. S-Log2 is designed with highlight preservation in mind while S-Log3 helps capture greater tonal range in shadows and mid-tones. The Sony α7 and α7R have the model numbers ILCE-7 and ILCE-7R respectively. In addition, the α7S, the α7II, and the α7RII have the model numbers ILCE-7S, ILCE-7M2, and ILCE-7RM2. Sony's new model naming prefix strives to unify model names. "ILC" stands for Interchangeable Lens Camera, followed by an indicator of A-mount "A" or E-mount "E". [5] So the SLOG base ISO of 3200 was chosen why? I get that its for video but there has to be a reason Sony chose it for this particular sensor."Both cameras make a good choice for this type of photography and pros are divided about which to opt for. However, the A7 IV wins out for many because of the smaller file size, excellent noise control and more affordable price. Only at 4s and above after Fw2.10, upgraded algorithm after Fw4.0, not present in continuous shooting mode [33] Neither camera has impressive burst speeds, but the A7S does a bit better, with a maximum of 5fps when using the Speed priority mode (meaning that capturing the shots is prioritised over focus accuracy). If you want focus priority, the speed lowers to 2.5fps. I don't pretend to have the correct answer but my post needs to be understood as a loose idea, hence I said "believe".

you have any interest at all in shooting video. Its sophisticated video capabilities make the a7S II the undisputed champ in the a7 stable when it comes to movies. This sigh of relief is compounded by new features and enhancements that make day-to-day shooting and video capture a seriously future-proofed treat – for example, there's support for the new HEIF photo format, H.265 video capture, and clean 16-bit raw output at 4K 60fps. The most attractive model is likely the A7 II. It won’t quite match the ISO performance or dynamic range of the A7 III, but it still uses a 24MP sensor capable of producing some brilliant images. For still photographers on a budget who want to move into full-frame, its low price makes it quite enticing. The third generation A7 cameras have an incredible autofocus system. It means the A7R IIIA and Sony A7 III are capable of focusing on a fast-moving subject and keeping it sharp wherever it roams around the frame.Both cameras record Full HD, but with the A7S you can select the XAVC S codec which raises the bitrate to 50Mbps as opposed to AVCHD (28Mbps). Furthermore, the A7S can reach 120fps in HD (1280×720) but with an APS-C crop (1.5x). Landscape, still life and macro photographers are usually concerned with capturing lots of detail. That makes a high-resolution camera the logical choice and the 61Mp Sony A7R IVA is the model of choice. In addition to its ability to record lots of detail, it has an excellent dynamic range and a superb autofocusing system.

Also, you say 'if the camera doesn't feel it has enough light it will open up the aperture further' - that's exactly where the problem lies, b/c the camera's algorithm for determining if it 'feels it has enough light' needs to be more conservative. Often it think it has enough light, but it doesn't - not enough to focus fast, anyway, so focus slows down. You then have to literally shut off like all the lights to get it to open up the aperture all the way. So at best, it's slowing itself down; at worst, it causes itself to fail. you need to shoot in low light. Whether it’s night-time cityscapes or basement gigs, the a7S and a7S II’s superb low-light performance will ensure that you get the shots you need. The sensor also has an extended ISO range of 50 to 204,800 and can fire its electronic shutter as fast as 1/32,000 of a second, a fast enough speed that rolling shutter distortion is much less of a concern than with other electronic shutters.

Capable of 4K 120p with super-fast AF of 0.2s and 15-stop wide dynamic range, the A7SIII also boasts a double stabilisation system that’s supported by a larger battery capacity so your content creation can go on, and on, and on… you get the idea. Best for High-Quality Videography But if you do shoot a fairly balanced mix of photos and video, and need a powerful hybrid camera that'll last you for years, then the Sony A7 IV should be right at the top of your shopping list. So while we all love the latest and greatest tech, you can save a lot of money by buying a model from the prior generation, money that could go to lenses, flashes, or other accessories that may make a bigger difference in the quality of your images. If you don’t need the latest speed and features, the A7 II, A7R II, a7R III or A7S might be the right camera for you. Some of the biggest advances in Sony cameras have been in the autofocus system, but even its first full frame mirrorless A7 has a hybrid phase/contrast-detection autofocus system. It doesn’t have the in-body SteadyShot INSIDE system introduced in the Mark II versions, but many Sony FE mount lenses are stabilised, and there are such things as tripods – and with the money you save on this camera, you can afford a decent one. ISO range: [Stills] 80-102,400 (Standard), 40-409,600 (Expanded), [Movies] 80-102,400 (Standard), 80-409,600 (Expanded)