Sony Announces A7Riv

Sony made a live video presentation this morning (7/16), introducing their latest camera, the Sony A7Riv. Among the highlights, as best I can recall, are

• 60.1 MP
  
• 5.76 MP EVF
  
• 6K video, 4K native Super-35
  
• Dual UHS-II card slots
  
• 16 frame, 240 MP Pixel Shifting
  
• Over 550 Phase Detection Points
  
• Real-time Eye AF in video mode
  

Of particular interest to me, the Exposure Compensation dial now has a center lock. I have unwittingly changed that setting many times, mistaking it for the rear dial, but more often, simply by keeping the camera from swinging on a shoulder strap. The new EVF has the highest resolution available on any camera, including the Fuji GHX100c. Even with the current A7Riii, I can focus accurately without using magnification or peaking.

 

Both the current A7Riii and A9 have been deeply discounted recently. The A9 is again at the sale price of $3600, after briefly returning to the MSRP of $4600. In part, this is a response to competition from Nikon and Canon. However extended sale prices are often a harbinger of new models impending.

 

The price is US$3500, with availability in September.

That sets a high bar going forward.

 

It will be interesting to see how this eventually translates into a midrange A7iv, if at all (perhaps the A7Riii gets handwaved into the A7iii slot, unless Sony has one more very compelling 24MP trick up its sleeve).

An A7Siii would make a compelling 24 MP offering, except it is hard to top the A7iii for video. Possibilities for an A9ii are nearly endless, including a fully-weatherized body with a built-in grip. How about a non-rolling shutter? That's already a feature in the Sony FS5 video camera, in Super-35 format.

132 line-pairs per millimetre across the frame is going to push a lot of lenses very hard..... and as for 264 lppmm? Ridiculous!

 

Sony's lens design team had better go into overdrive. Zeiss might be sweating a bit too.

It depends on how you define resolution. Most MTF charts display contrast vs distance from the center of the image at various resolutions. The finest line on most charts is 50 lp/mm or less. These charts show resolution from corner to corner, with some indication of astigmatism (when the sagittal and tangential lines diverge). The useful limit is arbitrarily defined as 50% contrast.

 

In times past, resolution was measured using high contrast fine-grained film. Modern machines measure MTF from aerial images, which are independent of any medium such as film or the camera sensor itself (e.g., DXO, ImaTest).

 

The same data can be displayed as contrast vs resolution, usually in the center of the lens. The ultimate resolution is where the contrast is zero - no information can be extracted from the response. Measured in this way, it is not uncommon for modern FF lenses to exceed 400 lp/mm. 110 lp/mm for an A7Riii is no theoretical challenge, nor would I expect 130 lp/mm from an A7Riv.

 

I know, from personal experience, that objects in nature can be resolved to the nearest pixel. Examples include spider webs and violin strings, from a distance (or loose bow hairs). To do so consistently, you need to use extreme care focusing and keeping the camera steady, including electronic (front) shutter and a flexible release cable or self-timer. In all cases, these are relatively bright objects against dark backgrounds, with length to distinguish them from hot pixels.

While a 20% increase in resolution is significant (spec candy), other features of the model 4 are probably more important in the long run. More hands-on results are appearingon the internet. An EVF with 40% more resolution than the A7Rii is a great help for viewing and focusing. However to get that resolution, you have to choose the lower update frequency of 120 fps or 60 fps. Video is still 8-bit, which makes the use of S-Log gamma problematic (in practice, no noticeable noise in good light). For reasons known but to Sony, the Super-35 cropping factor is 1.3x at 24 fps and 1.8x at 30 fps.

 

There is still significant rolling-shutter effect in both still and video. The scan time is about 1/15 second, compared to 1/150 for the A9. Global shutters are currently found only in APS-C sensors or smaller. Using the mechanical shutter helps, but does not eliminate the rolling effect, which is inherent to focal plane shutters too,

 

Focusing can now be done with the aperture wide open, like in a DSLR, by choosing "Focus Priority" mode. This increases the shutter lag somewhat, as the aperture must close first. In current cameras, the aperture closes as soon as focus lock is attained (Live View = off). This sounds like a firmware fix, not a structural change.

 

For a while, new A7Riii cameras will be available at (probably) greater discounts. If I were buying a new camera, I'd probably get the Riv. Having an Riii, I see little reason to upgrade.

Measured in this way, it is not uncommon for modern FF lenses to exceed 400 lp/mm.

Name one.

 

"Examples include spider webs and violin strings, from a distance (or loose bow hairs)."

 

Those aren't line pairs, they're single bright lines that spread in the lens transfer function/point-spread function. If two such adjacent lines can't be separated, then that's not real resolution.

 

The fact remains that resolution claims of 400 cycles/mm are pure fantasy unless monochromatic light of short wavelength is used. It's unachievable in practical day-to-day colour photography. As would be a true resolution of 240 cycles/mm over any meaningful percentage of the frame.

Edited July 18, 2019 by rodeo_joe|1

Those aren't line pairs, they're single bright lines that spread in the lens transfer function/point-spread function. If two such adjacent lines can't be separated, then that's not real resolution.

My example consists of two dark areas separated by a bright one, as opposed to a single dark to bright transition.

Another easy test is to shoot a star field. Take several exposures at different settings. It's easy to overexpose stars. Unless significantly underexposed, star images consist of a bright central pixel surrounded by another row of dim pixels. The image is elongated at the pixel level, due to rotation of the earth, unless you use a motor drive or very short shutter speed. Brighter stars tend to spread more, probably through scattering in the sensor. The dimmest stars are only one or two pixels wide (the second being dim). The Loxia 85 is one of the sharpest lenses in my collection

 

The bright star is in the middle of the belt in the constellation Orion. This is a 500x500 pixel crop at full size. You can enlarge it to see individual pixels.

 

Sony A7Riii + Loxia 85/2,4, 10 seconds

This resolution is something I have wanted for a long time for landscape cityscape and more. 60.1 MP, this is going to give results similar to medium format and making this affordable. Sony isn 't giving Canon or Nikon a chance to catch up.

The pixel-shift option can be used for landscapes, doubling the effective resolution (re A7Riii results). Sony's Imaging-Edge software or equivalent is required to render the results. However, Imaging Edge is sensitive to any movement in the subject, like blowing leaves or grass. Third party software, PixelShift1DNG, works much better, with few if any artifacts. It also finds, analyzes and renders all pixel-shift sets in a directory as a batch, rather than manually, one set at a time.

Doesn't really matter, it is still 24x36:)

OK, what should be a minimal shutter speed to shoot handheld with the sharpest 50 mm?

If I used it in zone focusing method, would the cureent aperture be enough or it should be stopped down more?

What should be a laptop to convert/develop its raw files? Only MacBook pro of top series?

What I can say I liked the quality of samples on Dpreview.

The use of vintagesque lenses (Voigtlaender 35/1.2, 40/1.2, 75/1.8) and Canon 50/1.2L and oldtimers via adapter seems to become impossible or useless.

Doesn't really matter, it is still 24x36

and still under $10K ;)

OK, what should be a minimal shutter speed to shoot handheld with the sharpest 50 mm?

With IBIS, you can get sharp images with a 50 mm lens down to 1/8 second, possibly slower. "Zone Focusing" implies street (candid) photography. In that case, there is a contest between slow shutter and subject movement. I generally use auto-ISO with an upper limit of 27,400. In a practical situation, I can get useable night shots in light too dim to read the dials.

 

IBIS is not as good as a tripod. If you want to get full use of 60 MP (or 42 MP), a heavy tripod is essential, combined with an electronic shutter and a cable release (or 5 sec timer). Any GM lens will suffice, and probably newer G lenses as well. The 24-70/2.8 GM is my go-to lens, but I'm partial to Zeiss primes for landscapes, also well inside the Goldilocks zone.

 

Uncompressed raw files from my A7Riii are about 80 MB, which translates to 120 MB for the A7Riv. Derivative JPEGs are smaller, but TIFF files are over three times as large. Processor speed is not especially important, but for efficient image processing in LR or Photoshop, you should have at least 16 GB of RAM. I use a 13" MacBook Pro (2017) with a 1 TB SSD. Drive speed is important too, but you can supplement the internal drive with an external SSD for speed (300-550 MB/s via USB3 or TB), or a 7200 RPM HD for extra space at up to 130 MB/s.

 

This was shot in downtown Dublin, IR, hand held, with a 3 shot HDR bracket. 1/40 @ f/5.6, ISO 1200

 

Sony A9 + Sony 24-70/2.8

UHS-II cards download much faster than UHS-I, about 80 MB/s in my Kingston UHS-II reader, via USB3. The raw files load 4 at a time.

 

Before the MacBook Pro, I used a Lenovo Thinkpad without any speed problems. At my desk, I use a 2017 iMac 5K. The iMac is special, since I need to edit up to 3 streams of 4K30 video simultaneously.

and still under $10K ;)

Pentax 645Z under $10K too.

Pentax 645Z under $10K too.

The X1Dii is tempting, and it would work with my old CF lenses. I know the Hasselblad is only 50 MP, and not really "full frame" medium format, but hey. A lens of equal quality has 30% more potential resolution* with cropped MF than on a FF small format camera. Best of all, the X1D is well under $10K and it's not a Pentax.

 

I have tested my CF100/3.5 on a Sony A7Riii, and it compares favorably with Sony lenses near that focal length. I have an original CFV16 back, which compares well with Sony 24 MP images. I have no problem with shooting medium format - within 100 yards of my car.

 

* To a good approximation, the net resolution of a system is the root-sum-square of uncertainties of the lens and sensor combined.

Just wondering, who needs 60 meg files at 16 frames per second?

Just wondering, who needs 60 meg files at 16 frames per second?

With 60 MP to play with, you have the ability to crop severely and still have a useable image. I'm not sure where 16 fps comes from, but at 10 fps you can take a short burst of a speaker, conductor, or subject in any situation where a particular expression, mouth or hand position makes a difference. I find my batting average is very high in finding at least one frame which flatters the subject best.

 

I take many landscapes with bracketed exposures for HDR rendering. You can never have too many pixels for landscapes, and with 10 (or 20) fps, you can shoot the set of exposures very quickly, without a tripod, and with little movement between frames.