The best 50mm for A7RII

After testing the Sony Carl Zeiss 55mm f/1.8 FE in 2014, I was less than impressed. I may have had a decentred example (it happened to dPreview and at least one photographer I trust to know his lens performance expectations). It was, certainly, pin-sharp on a test chart or a brick wall but the moment three-dimensional subjects were involved at wide aperture the defocused detail could be very untidy. The clip below from trees behind a building which was sharply focused is at f/1.8 and 1/2500th (a suggestion that it could be caused by camera shake is easily ruled out). See my additional notes at the end!

It’s worth saying that when I had this lens I made some tests of the bokeh using very strong defocus which looked good. Many examples I’ve seen, which true believers put forward, show a figure (from full length to portrait) centre of a horizontal frame at f/1.8 with a pleasant enough looking distant background. My gripe has been with what happens when your subject is further away, or the background is not all very distant. This is an expensive lens but it seems to me to have fussy bokeh with too much CA fringe and also more focus-related colour shift than desirable.

Here is a full size example with EXIF. Honestly, the best standard lens around? //www.pbase.com/davidkilpatrick/image/162847304

Now I’ve got a fair collection of 50, 55 and 58mm lenses and also the little Canon 40mm f/2.8 STM which is my alternative to having a 35mm and a 55mm. No matter what the lens – Pentax, Minolta, Sony 50mm f/1.4, Helios, Zenitar, Nikon, CZ Jena – the full aperture between f/2 and f/1.4 always proves to be a touch soft. They all have residual aberrations that the CZ 55mm f/1.8 design has eliminated. While they can have a smoother bokeh, they also have marked colour shifts and uncorrected CA. Generally, they also all perform extremely well once stopped down to f/8 and most designs are great by f/4.

Despite the advantage of full AF functions, the CZ 55mm does not have a particularly good close focus or maximum image scale. In use I often found myself framing up closer than 50cm. That’s half a metre – it’s even further than the old 55 and 58mm lenses of the 1960s, which generally manage 45cm. I find this limitation hard to understand. 50 years ago CZ Jena started to put helicoids on their standard 50mm lenses which enabled focus down to 35cm. We have gone backwards since then.

And then I realised I’ve already got a lens which is free from all vices, gives me AF and manual focus options using adaptors I already own, which cost me about a third of the price of a CZ 55mm – and I was not being used on my A7RII. We bought a good used example of the Sony SAL 50mm f/2.8 Macro to use with our Alpha DSLR.

First of all, I compared this with the idea of buying a Zeiss Loxia 50mm f/2, by fitting it to the LA-EA3. Although the focusing ring does not communicate to the camera to invoke magnified manual focus, the lens has a Focus Hold button which can be set to this. The focusing throw is steep but in practice very accurate focus is easily set. At f/2.8, the lens is already perfectly sharp with some contrast improvement at f/4. The lack of vignetting and distortion, the flatness of field and generally very attractive smooth defocusing without CA issues make the lens better than typical fast standard designs.

On the LA-EA4 with autofocus, a limited set of AF functions ends up activated and there’s always the issue of the slight delay and sound caused by mechanical aperture operation. AF-C is of limited use, along with this video functions. However, I don’t generally use this type of lens for action or for video.

I made plenty of non-image tests by defocusing bright edges, both ways, and could find no hint of colour problems. I then set up a small food shot using the close focus – exactly the reason I find a lack of close focus restricting – and made tests at f/2.8, f/5.6, f/11 and f/22 to look at the bokeh. My conclusion is that I will be hard pressed to find anything technically better, or with a more pleasant character to the background defocus, in the c.50mm focal length. The series covers all four apertures.

I am aware that one comment will be that f/2.8 simply isn’t wide enough. There’s no significant differential focus and you’d need 50mm f/1.0 to get what many photographers want. However, this is all to do with viewing size. We all tend to see pictures on smartphone screens, on Facebook, or even on our own camera three-inch screens. In fact, at f/2.8 there isn’t enough depth of field for a typical real-world use of a full page reproduction and f/5.6 is just about right. For a poster, f/11 would be good. At f/22 the whole image is slightly softened as expected and it’s just there to complete the set.

For the moment – at least until a Batis version of the 50mm f/2 Makro Planar appears and answers all my demands perfectly – I think this Minolta-derived 50mm macro will do fine as my ‘standard’ lens.

David Kilpatrick, aka ‘some random blogger’ (©SAR comments March 2016)

Added August 30th 2016: Sony has announced an E-mount 50mm f/2.8 Macro focusing to 1:1 with a stated RRP of $500 – really, they must have read this article in March. In the meantime, during the Brexit fiasco I caved in and bought a 55mm f/1.8 CZ, suspecting the price would be 20% higher soon enough (and sure, it was). My new example is no better than those I originally tested but it has its uses and in a flat plane – no defocused image to screw the results up with an ugly mess – it’s the sharpest 50-55mm I have used. I’m still using the 50mm macro and recently spend a month using the Samyang 50mm f/1.4, which is not as sharp as the CZ but handles blur and bokeh more elegantly. Both lenses don’t really excel at suppressing Longitudinal CA, one of the strengths of the A-mount macro. Hopefully the new SEL FE 50mm macro will also give clean, colour-shift free foreground and background bokeh.

Added July 29th 2017: I have now bought the 50mm f/2.8 Sony FE Macro, and put my A-mount macro lenses up for sale. The E-mount focuses to 1:1 rather closer than I would like, at 16cm which indicates its internal focusing changes the focal length to something more like 37mm to 1:1 (16cm is a pure 40mm at 1:1 assuming no optical thickness to the lens). It’s an extremely sharp lens with bokeh as good as the A-mount 50mm and no trace of CA.