CAMERA



DSLM in direct comparison - Part 1 (of 2)

Pros and cons of actual DSLM in direct comparison.

By 2018 at the latest, the market for DSLM cameras has become somewhat more confusing again. 

After Canon had helped the breakthrough of full format videography with the EOS 5D in 2005, Sony conquered a large share of the steadily growing market from 2014 with the Alpha7s and the Alpha 7s II not two years later. Also in 2014 Panasonic started its success story with the Lumix GH4 . Its successor, the Lumix GH5 , became a bestseller starting in 2016, despite a the smaller Four-Thirds sensor.

In 2018 and 2019 the Z6 and Z7 models by Nikon, the first mirrorless camera from Canon called EOS R as well as the full-format DSLM S1 and S1R from Panasonic joined the round.

The long-awaited announcement of Sony's Alpha7s III is still about to come.
 
This article gives an overview of the current status in this segment and compares the most important mirrorless cameras for videography. Since the Canon 5D IV despite the DSLR system still is an important model, we have added it to the DSLM focused comparison table.

In this article the central advantages and disadvantages in comparison to each other are in the center. Find the complete overview as table as PDF for download attached.

For even more detailed information, we recommend the separate articles on the individual models in our app.

The following models are included (May 2019):

Blackmagic Pocket Cinema 4K
Canon EOS R
Canon EOS 5D IV
Sony Alpha 7S II
Sony Alpha 7 III
Panasonic Lumix GH5/ GH5s
Panasonic Lumix S1/ S1R
Nikon Z6/ Z7


Sensor Size and Light Sensitivity

The size of the sensor plays an important role for image quality and light sensitivity as well as for image aesthetics.
Full format sensors are very much in vogue. They offer a high resolution, allow a better light sensitivity with lower noise and offer the popular background blur (bokeh) even at medium aperture values.

However, depending on the application, they do not always have exclusive advantages.

The high purchase price for full format systems is certainly not unimportant for this segment. This applies both to the actual camera body and to the associated optics. Since full format sensors also require lenses with a larger image circle, they are more expensive than "smaller" lenses.

Also the weight should not remain unnoticed. Full frame lenses are much heavier than their APS-C or MFT siblings.

The popular "cinema" look, on the other hand, can be achieved relatively easily in full format with an F4.0 or even F5.6 aperture. This is the usually found minimum aperture for standard full-frame zoom lenses.
However, a comparable bokeh as in full format with aperture F4.0 can be achieved in APS-C with an aperture of about F2.8 and in Four Thirds with an aperture of F2.0. The current standard zooms for MFT, e.g. from Olympus or Panasonic, already offer an aperture of F2.8. A standard zoom for MFT with an aperture of F2.0 is announced for this year. It remains to be seen whether this will still be cheaper than a standard zoom for full format with F4.0 aperture.

You should also note that some models work in "window mode" when recording in 4K/ UHD and/or slow motion. This means that the sensor is cropped and recorded with reduced sensor area.

In terms of light sensitivity and noise behaviour, a large sensor plays off its advantages especially well. Due to the larger sensor area, the light-catching pixels can remain relatively large, even at high resolution. As a result, they capture more light (photons) and thus cause a higher light sensitivity of the sensor.

Traditionally, the Sony Alpha 7 series deserves special mention here. Especially the Sony Alpha 7s II, which reaches a unique maximum ISO value of 409,600. Of course, in practice it is hardly possible to deliver usable images with such an extreme ISO value, but it shows that the image noise of this model can be controlled well even at very high ISO values.

The dual-base ISO introduced by Panasonic, however, also enables amazing results despite the comparatively small Four Thirds sensor. Nikon and Canon deliver very good results as well. The GH5, in which this system is not yet integrated, falls somewhat behind. But in comparison, the Alpha 7s II remains the clear front runner.



Contrast Ratio

This is especially important if you want to capture very contrasting motifs, for example a classic wedding couple in the sun (white wedding dress, black suit) or people with windows in the background in interior shots, without losing too much detail in the shadows and highlights.

Using special gamma settings (LOG) or HDR modes, the maximum possible contrast range of the sensor can be used. Not to forget, however, that the compression by the codec as well as in  distribution channels makes it smaller again. Also the combination of LOG with 4:2:0, 8bit codecs, quickly leads to the limit, which can often be seen, for example, in less beautiful skin tones.

The maximum contrast range given in this comparison represents the best possible range that can usually be achieved with LOG.
Here the Blackmagic Pocket Cinema 4K (13 steps) and the Sony Alpha 7S II (14 steps) are close together. But all others, with the exception of the somewhat older Canon EOS 5D IV (10 steps), still offer an excellent 12 f-stop contrast range.

A classic TV picture in Standard Dynamic Range (SDR) is seen with a contrast range of approx. 8 f-stops. Modern HDR monitors already have over 10 f-stops.
For comparison: the human eye is able to detect in about 20 f-stops.



Color Subsampling

The depth or fineness of the displayed color or gradient is technically limited by the color subsampling of a codec. With an 8-bit codec a maximum of 256 gradations per colour tone can be displayed, with a 10-bit codec there are already 1024 gradiations. 4:2:2 also enables a more accurate colour representation than 4:2:0.

Although for example the Nikon Z6/Z7 can output a 4:2:2, 10bit signal via the HDMI output, it records internally on the memory card with 4:2:0, 8bit. If you have the possibility to use an external recorder (and the additional weight is not disturbing), the internal limitation is no problem here. Until the introduction of the Lumix S1, Nikon was the first manufacturer to make it possible to record 4:2:2 in 10bit with a full format camera.

The Four Thirds models of the Panasonic Lumix series as well as the Blackmagic Pocket Cinema 4K, which works with almost the same sensor as the GH5s, are outstanding in colour subsampling and signal processing.

The Lumix GH5 / GH5s and the full-format DSLM Lumix S1 (after a firmware update) can record internally with 4:2:2, 10bit. The Blackmagic offers an internal recording in 12bit RAW or 10bit ProRes.



Read part 2 next week here at DPP Film Tech App.

Downloads:
DSLM complete comparison table

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