Tuesday, 22 January 2019

Shallow Normal (bigger is actually better)

pretty much as soon as I got into digital cameras (like 18 years ago) I loved them for their ability to make quick pics and be able to send them via email to my friends (I was in Japan and my friends in Australia) or put them on my blog. Great stuff and (sadly) I haven't exposed processed film since 2014 and really since 2009 in developing my own.

While digital cameras have featured increasingly in my photography it has not always been with a view that they are universally "better". One thing missing (which I've blogged about a lot) is the lack of a normal lens which gives a pleasing rendering and a shallow depth of field. This was eventually satisfied for me with the Panasonic 20f1.7 and later the more commonly thought of "normal" the 25f1.7. It was pretty much 80% of my desired needs for focal plane control.

Naturally as soon as I got my A7 and put my FD50mm f1.4 on it (and took some shots) I was sold. This combination was (as expected) everything that 35mm film with a 50mm was able to give me and the benefits of digital too.

This was clarified the other day with a few shots sitting around in a bit of forest I know (and like) near where I live. I took two shots sitting on a tarp  on the ground (because ... ants) of my bike, one with the Panasonic 25mm f1.7 on my GH1 and the other with my Sony A7 and the nFD 50 f1.4

To me both these images have sufficient focal plane control, however they are both different to look at. I knew that the 50 would be better on the FullFrame than the 25 on the m43 camera, but its always good to see these things. To equalise things (such as lens profiles)  I developed these RAW files into a TIFF with DCRAW and cropped the GH1 into 3:2 format. I found also that I had to use the Panasonic at f2.5 to get away from that "wide open contrast softness" effect, (see this post for images) but more on that contrast difference in a moment

Panasonic 25mm @ f1.8

then ...

FD 50 f1.4 @ f2

Background isolation on the m43 unit is acceptable (and better than any or most zooms), but its my view that larger formats are where mid range angles of view shine and the A7 and FD50 renders a very nice image with much more natural seeming background with a more film like graduation of dynamics than the smaller sensors can.

Both were at 400 ISO (so that's why the A7 image is a wee bit darker f2 vs f1.8 is about 1/3rd of a stop)

A recent discussion about a presentation on YouTube centering around the idea that "people can't tell the difference in prints between m43 and Full Frame" left me wondering if any of the participants had actually seriously looked at this. There are many factors involved and especially with use of Aperture selection and Wide Angle lenses one can take Depth of Field out of the equation, but other components like contrast as well as resolution make a difference. And by resolution I don't mean 1000:1 contrast ratio line pair charts, I mean photographs of actual subjects.

People often talk of wanting to print large (while poo-hooing pixel peeping). My personal experience is that a 50% view on a good screen (100% meaning 1 screen pixel = 1 file pixel) is about as good as you'll get for a comparison online of a large print inspected close. So lets look at what we see on magnification:

Panasonic 25

now I suggest you "right click" that above image and open it in a new tab to see it unscaled by browser / blogger.


To me the FD holds up the best. Now it may surprise you to see how little cropping was done to take the overview (which started life as 4000 pixels wide) down to 2000 image pixels (no scaling) to see what one would see on a print from the 4000 file; but that's one of the facts of life.

Now the A7 gives 6000 pixels and so to keep "feature size" the same I chose to scale the A7 first back to 4000 then down to 2000. If I'd kept it at its native size it'd be like this:

highlighting a couple of things:

  1. how much larger a print you can make with the A7 without pushing it (1 meter x 68cm) vs the GH1 (68 x 45cm) with both printed to 150dpi because myself I've found that works fine without resizing for large prints
  2. how much better the picture stands up (both in pixels and in tonal range, look at the blowouts on the tree)
Looking at 100% pixels make is clear the advantage the A7 has over the GH1

and ... the same area 

Also, having recently compared the GH-1 to the latest G80 I'm not convinced that the GH-1 is significantly weaker, meaning that a G80 would still not render as well as the A7 has (and the used A7 cost an amount less than a used G80)

Contrast and clarity

One of the points in favor of the micro43 system is that people argue that many lenses don't have to be used "stopped down" to achieve adequate image quality. I would argue that this is not in fact borne out in practice. For instance the review here on the 25 suggests:
In a word: exceptional. The Lumix 25mm ƒ/1.7 provides sharp images straight out of the gate at ƒ/1.7, and while stopping down technically provides statistically sharper images, you'd have to peep pretty closely to see any kind of practical difference.

Yet this is not what I've observed, if you look again at the f1.8 segment (which is essentially the same as f1.7) is lacking strongly in contrast and sharpness. Ignore completely that there are any DoF differences because when you look at the above 2 segments DoF is simply not an issue; look at the footpeg or the word "YAMAHA" on the cover. As much as I want to say "theres no obvious difference" there indeed is.

I didn't present the images shot with the Panasonic at f2.5 because lighting changed between my first set (pairs of images with GH1 and A7) and my second set, however I think its clear that the m43 system will essentially have significant shallowness of DoF at f2.5 nor any "speed advantage" conferred by using a wider aperture. The FD50 on the other hand could be stopped down to f5.6 and its image clarity would simply continue to improve (over the f2 presented)


So before anyone says "you biased it" ... well sorry, I didn't. I have no reason to bias this because I'm not trying to convince anyone. I'm just presenting my own exploration of gear I already own (as I always do).

This does not mean I'm some forum tosser about to write "I'm dumping my m43 gear" because it makes a great light weight kit for travel / general picture taking and unless one is pushing the limits one just won't notice most of this.

However when I do want to go out and (with something specific in mind) make a high quality capture of something which I approach with care then I'm glad to have the A7 in my arsenal ... cos I just haven't been using the 4x5 lately (and colour negative sheet film is getting hard to get processed these days, not to mention expensive).

In the above I have attempted to show that there are distinct differences between the formats (m43 vs FF) which a photographer can make use of to produce a print (even A4 sized) which can be identified as different by any astute observer.

Hope that helps someone

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