Sunday, 1 September 2013

New manual focus wide angle prime from Samyang

News has surfaced that Samyang will release an very wide prime lens, specified as 10mm f/2.8. So is this finally the compact wide angle prime that I have been waiting for?

No, it isn't. It is far from compact, as illustrated by the following comparison table:

LensSamyang 10mm f/2.8Lumix G 7-14mm f/4Olympus 12mm f/2
Length106mm83mm43mm
Diameter86mm70mm56mm
Weight710g300g130g
Minimum focus distance0.25m0.25m0.20m
Lens elements/groups14/1016/1211/8
Filter threadNANA46mm


Both the Lumix G 7-14mm f/4, which is extremely wide, and has a zoom, and the Olympus 12mm f/2, which is one stop faster, are much smaller and lighter than the upcoming Samyang lens.

So why are Samyang making the lens so large and heavy?



One thing to keep in mind, is that Samyang makes their lenses out of metal, which tends to be more heavy.

Cross-format design


But the most important reason is that this lens is not designed for mirrorless cameras in the first place. It is designed to be used on a number of formats, up to APS-C in sensor size. While APS-C is a larger sensor size than Four Thirds, this is not the reason for the much larger lens. Rather, the reason is that it is also designed to be used on SLR type cameras, with a significantly larger register distance than most mirrorless cameras.

The larger register distance means that wide angle lenses must be designed with a retrofocal construction, requiring large, curved front lens surfaces. This is why wide angle lenses for SLR cameras are large. It is also the reason why the Lumix G 7-14mm f/4 is comparatively small: It is designed for use on a very short register distance.

It's not the first time Samyang does this. They also have the Samyang 16mm f/2, which is designed for use on both SLR and mirrorless cameras, and, hence, is very large.

Samyang 16mm f/2Samyang 16mm t/2.2 cine version of the same lens

Are people going to use the upcoming Samyang 10mm f/2.8, given the huge size? Yes, I think that it could be a popular lens among some select people, especially those who are into movie making, and don't worry too much about the size of the gear. They will like to have a well dampened manual focus ring, and also to be able to change the aperture steplessly and smoothly.

For Samyang, it makes more economic sense to make one lens design to cover both SLR and mirrorless cameras, rather than making two separate, different lens designs.

One example of a wide Samyang lens which was designed for Micro Four Thirds in the first place, and, hence, is very small, is the Samyang/Rokinon 7.5mm f/3.5 fisheye lens. I think this fisheye lens has very good optical quality, and represents very good value for money.

Short register distance makes smaller wide angle lenses


One illustrative example of how a short register distance makes wide angle lenses smaller is the comparison between the Olympus and Panasonic versions of the 7-14mm extremely wide angle zoom lenses. The Olympus version is designed for the Four Thirds format, with a register distance of 39mm, while the Panasonic version is designed for Micro Four Thirds, with a register distance of 20mm:


Olympus 7-14mm f/4 and Lumix G 7-14mm f/4 compared, to scale

Software image correction


Finally, another reason why the native Micro Four Thirds wide lenses can be made smaller, is the use of software image corrections. Many Micro Four Thirds lenses require in-camera geometric distortion corrections for the images to come out rectilinear. Additionally, some Panasonic lenses get software Chromatic Aberration (CA) adjustments when used on Panasonic cameras.

These software image corrections allow the designers to make the lenses smaller and simpler, while retaining the quality image output that people expect.

The Samyang lens cannot utilize software image corrections, since it is a manual lens without any electrical contacts. Hence, the camera will not recognize what lens it is, and cannot apply any corrections. Also, as it is designed for use on SLR cameras, where software image corrections would be impossible, the lens cannot rely on these post processing corrections.

Other Samyang lenses


According to rumours, Samyang is also going to release a 12mm f/2 lens, which is actually designed for mirrorless cameras in the first place. It is probably going to be much more compact, and a real alternative to the Olympus 12mm f/2.

Conclusion


Even if mirrorless cameras are growing in market share, some third party manufacturers still make lens designs based on SLR cameras. This results in larger than necessary lenses for users of mirrorless cameras. The Samyang/Rokinon 7.5mm f/3.5 fisheye lens is one of the few third party lenses specifically designed for use on the Micro Four Thirds format.

One gap in the Micro Four Thirds lens lineup is a compact extremely wide angle prime lens. It seems that the announced Samyang 10mm f/2.8 is not going to fill this gap. I'm hoping that Panasonic or Olympus brings out something like a 9mm f/4.5, or thereabout, prime lens. That should be possible to design quite compact, and for a price of around $300, which I think would be a huge hit.

2 comments:

  1. I think that the 10mm f2.8 becomes a bit more interesting when combined with one of the telecompressors available for m43 now. Assuming it has a big enough image circle to cover m4/3 on one of these compressors, it would become a 7.1mm F2 on a 0.71x converter. Suddenly much more interesting and worth the size and weight at 2 stops faster than either existing 7-14mm lens. And the 16mm F2 becomes an 11.6mm F1.4.

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    1. The lens covers an APS-C image circle, but probably not more than that. If you want to go this route, then you must purchase the lens with a SLR mount, e.g., Nikon F or Canon EF. Only then is there space for the telecompressor between the lens and the camera.

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