really wide lenses (sort of a Bambi vs Godzilla redux)

premise

I feel that the Micro43 system (m43) is the low hanging fruit of camera equipment, it provides a level of compactness which is more or less unchanged by further dropping down sensor size, like the Nikon 1 Series which didn't really provide more compact cameras nor lenses. The lens range of the system is huge and indeed the availability of legacy 35mm lenses is presently far in excess of what the market can soak up (literally tons of good 35mm lenses can be bought and adapted) and adds to the system too.

The sensor isn't too small to afford reasonable focal plane control (shallow DoF), and indeed is almost the same as the very popular APS format (which indeed Canon released its first DSLR in way back in 2000 with the EOS D30 camera.

Its ability to do High ISO is of course limited compared to larger formats like Full Frame and or Medium Format Digital, and while latest m43 sensors will indeed go almost as high in ISO, you will be losing in colour fidelity and general bit depth (hello blowouts and posterisation).

I'm no longer on the path of having the latest and greatest (principially because I think we're already close to the crest of the diminishing returns crest) and so when I picked up the A7 it was a $500 experiment (rather than a $2000 experiment just 6 years ago) to allow me to see and confirm if there was something of value in this for me.

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One of the things I enjoy having in my camera outfit is a very wide lens. Myself I've been inclined to this for decades, however anything wider than 24mm has often been outside my budget.

Micro43 brought along the equivalent of a 22mm lens (in the guise of the GWC-1 adapter for the Panasonic 14mm f2.5 lens) , which has been both my widest lens (lets ignore my Olympus 21f3.5 for the moment, not least because I sold it years back and I've only tried it on a 5D mk1) and a mainstay of my wide angle photography. Its enabled me to get some shots I enjoy in places, like this one in the Czech Republic in a dimly lit subway under maintenance.

Certainly no phone would have done that (either in angle of view or high ISO performance.

So given that I'm testing out the limits (and how I sit with the results) of my new (to me) Sony A7 I felt the need to find an equal for that angle of view.

Having read and seen good things about the FD 20mm f2.8 I decided to buy one. Sadly the prices have gone up since the A7 came out. This is probably because a 20 is within what one calls "normal" on m43 and almost nothing else can manage its shorter (for 35mm) flange distance.

Appearance

This is what one (mine) looks like on a A7

which may not be what you were hoping to see, but actually isn't too far away from what modern 20mm lenses (and wider) are looking like today.

Another angle makes it clearer that this is not a compact lens:

The amount of "stand off" taken up by the adapter also makes clear how much "space" was taken up by the mirror box on the FD cameras, or indeed any SLR or D-SLR camera.

However it does make for a nice firm grip of the lens with the left hand while holding the controls of the camera with the right.

In comparison the above mentioned Panasonic m43 with the GWC-1 and 14mm lens compares like this:

and

The A7 is indeed a bloody compact camera (as indeed is m43), however its a fact that the lenses are needed and make the entire system thus different.

A key difference also being that the GWC-1 comes off (it essentially screws onto the filter thread) and leaves the very compact 28mm equivalent 14mm lens  ... which is pretty nice for general picture taking (although about the same angle of view as most modern phones). If you want to know more about the Panasonic 14mm f2.5 and the GWC-1 I recommend my blog post over here as a starter.

aside:

 I'd rather have my camera nicked or broken in the field when out touring internationally than my phone, so think about that when saying "I do everything with my iPhone"...

image quality

Well for a starter the A7 produces a 6000 x 4000 pixel image over the 4000 x 3000 that the m43 camera has, and so that's going to perhaps give it an advantage. However I'd argue that the optical system of the FD20f2.8 vs the combination of the P14f2.5 &GWC-1 (note, for simplicity I'm just going to call the combination of P14 & GWC-1 the GWC-1 from now on in this post) is such that the m43 system is limited by the optical resolution not the amount of pixels ... but lets have a look.

First its important to understand that in modern cameras and lenses lens corrections are built into the JPG files and stored in metadata on the RAW files. With a legacy lens like the FD20 there is no such thing available, it must be chosen and applied in post processing ... so to even up the playing field I always photograph in RAW and then develop my file with DCRAW.

So  lets have a look at the FD20 on the A7 . This shot represents the scene taken for all these tests

now the GWC-1:

... which is a camera JPG not a RAW sourced image. Its worth showing an overview of the GWC-1 as sourced from RAW file, as you'll see that the Panasonic corrections for the 14mm are not insignificant (and of course make a difference to what the GWC-1 produces.

So you get a bit more image width now, nearly as wide as the FD20, but with substantially more barrel distortion ... if you correct in software in post it will look closer to the JPG sourced, and of course you'll (as always) loose some of the width.

I think its worth pointing out that Panasonic designed the GWC-1 specifically with the 14mm f2.5 in mind (well and a PZ 14-42 as well), so its quite likely that they knew what corrections would occur and worked to fit in with that.

The FD20 is a little bit wider and needs less attention as its a nicely corrected rectilinear lens right out of the box (which isn't surprising because it was made for the days of film when there just wasn't an easy way to correct for this stuff - and buyers thought it important back then.

You'll probably have spotted some vignetting visible in both (the Panasonic corrects this in JPG a little, but not fully as there is no electronic coupling between GWC-1 and P14mm so it can't know its there to correct it. So lets look at vignetting

FD20

So strong at f2.8 and clearing up well by 5.6 but not observably better at f8 and (not shown) f11 is barely cleared up at all

GWC-1

where I didn't go past f5.6 because the lens system is already at it sharpest at f4 and starts to go down hill a bit due to diffraction around f8

You can see that the GWC-1 also has more barrel distortion, which depending on the subject may need some correction in post, the FD20 is much better out of the box.
Image details
As expected the FD is poor on the edges but not bad in the center from wide open, and gets better all over as you stop down. Again like vignetting I didn't see much in the step from f8 to f11

The following are 100% pixel crops from the TIFF files developed by DCRAW, what is interesting is how much smaller the same features are between the A7 and the m43 camera (yes, that 6000 pixel vs 4000 pixel makes a difference), so make sure you open these images full screen to observe that.

FD20 Corner

and by f8 the text of the ARSE postcard is visible (and the print of the plastic food container too).


GWC-1 (raw) corner

FD20 Center

The center however clears up so that even by f4 you've got quite good details on the black torch, the tooth picks and the swiss army knife.

GWC-1 center

and even at f5.6 (about the sharpest its ever going to get) its neither as large nor as sharp as the FD20 image at f4.

At this point I think it would be of benefit to anyone still curious to go and look at some other A7 lens comparisons and compare these both to my results and to other lenses. I happen to think the (excellent) blog of Phillip Reeve has some great tests which I strongly suggest you look at. Even if you're not a "Full Frame" person and instead are reading this because of the m43 content. I recommend reading his posts about

• the Canon FD20f2.8 (look at his edge and center shots which are close to my own findings)
• the Tokina Firin 20f2 
• and the Zeiss Batis 18f2.8

Consider the prices of those lenses and then that I paid

• $350 (including shipping) for this FD20f2.8 
• $150 for my GWC-1 (and I already owned the 14f2.5)

Discussion

So what does this mean? Again as I've mentioned I don't feel that this means "I'm going to dump my m43 outfit" (as is often said on internet fora) , what it does instead is highlight to me that my choices for a light weight camera which would also sit as an equal against my EOS APS camera (a 20D back then) has proven viable.

It shows me that the compact and light weight m43 system is far more than adequate, but virtually indistinguishable from my A7 in all but the largest of prints. For anything that will be web delivered (although 4K may change that a bit) the A7 is un-necessary.

I prefer to carry on holidays and day trips the Panasonic GF-1 and its small lenses, but when I want to go out and take an image I've planned and I know I'll want either bigger prints or to take advantage of higher ISO or to take advantage of more shallow DoF that Full Frame gives, then I'm glad I've got the A7

hope that helps someone else

 ... something else ...

Ouhh, and about the title, nearly 10 years ago I compared my Panasonic G1 (the very first m43 camera) to a Canon 5D MkII which I dubbed Bambi vs Godzilla ... so this is a nod to that article. I wrote that because I wanted to also examine what was the limits of sensors, as I knew that per square centimeter the G1 had a denser packed sensor than the 5D did. Indeed scaling up the density of the G1's m43 sensor I predicted that a Full Frame of the same density of 42 megapixels was possible. The A7 is only 24 megapixels, but indeed the Nikon D850 is  right there at 45 megapixels ... a standout camera even today.