Dawid Loubser wrote:
> .... Specifically, I am talking about my scratched, slightly busted 65mm
> C-series wide angle lens, with an
> equivalent of 32mm FOV.
>
> Have a look at this recently scanned slide (Provia 100, Epson V700) shot wide
> open (notice very shallow DOF,
> blurred foreground just to prove it's taken wide open :-) in very demanding
> lighting conditions. This is a
> torture-test for any lens, with extremely bright highlights all over the
> frame.
>
> http://www.deviantart.com/download/141023473/Cubana_Full_Size_by_philosomatographer.jpg
>
As image, separate from source, I rather like it.
Counterpoint:
I have no dog in this fight,as I have never owned a Mamiya lens or body,
nor do I see any likelihood of doing so in the foreseeable future.
Still, I can look at an image and notice some things about it. The
characteristic that immediately catches my attention is flare, and lots
of it. No, none of that string of stars and/or bright images of the
aperture you can get with sun, bright specular sources, or any very
bright, close to point source light.
What I do see it bright light spilling over into dark spaces all over
the place. Flare is when light that should be in one place as a
consequence of the refractive process that creates the images, including
its refractive aberrations, ends up in another due to scattering and
internal reflections in the optics.
A lens with no flare will reproduce a square of black tape on a
lightbulb the same as the tape on a gray card, with clear, sharp edges,
the tape all one, uniform black and the background on uniform tone.
Flare, light landing in the wrong place, will blur the bright background
over into the dark area.
I can't, of course say what effects in the image are due to film vs.
processing, scanning and post processing. However, given its
presentation as an example of lens quality, I assume it's all lens.
Looking at the image starting from top center:
- The slats at the very top level simply disappear where they cross the
bright lights behind them.
- The backlit "Ocean Buffet" sign on the right is almost unreadable.
Faded or flare? I don't know, but there is certainly flare evident in
the left one, too.
- Look at the circular line of fluorescent light on the next windows
down. Wherever it crosses the frames and closed umbrellas, it
significantly cuts into the vertical lines. Where it crosses the smaller
bars of the railing, it almost obscures them.
- Those same thin bars have a lighter line along the top, worse where
the back light is stronger. Flare - or - gasp - CA?
- They also are strongly affected further to the left, where the third
bright oval sign and a spotlight and what appears to be a reflection of
it flare enough to completely obscure them.
- The spotlights and chandeliers in the lower inside level are all blobs
larger than the actual size.
- Lots of flare washing out detail in the left central area.
- It's hard to tell from one image, but it appears to me that there is
some overall lowering of contrast on the face of the building, which may
be some overall flare. Could easily be film or scan, too.
As to CA, there may indeed be little or none, but with all bright-dark
edges obscured by flare, would it be visible if it were there? I don't
think one can tell from this image.
Sharpness?
- You've sort of taken the position that the fact that an MF image blown
up to the same size as a 35mm image and sharper is somehow proof that
the MF lens is sharper. Certainly a practical position to take for
someone who makes small to moderate size prints.
- Not the position taken by many advocates of MF, who claim the best MF
lenses resolve at least close to as many absolute lppms as the best 35mm
lenses. If thinking about shooting for very large prints, it's a very
significant difference.
- In any case, at the size presented, the scan is at about 1000 lines
per inch, not high enough to distinguish between even moderately good
lenses. There's no info here about how much resolving power the lens has.
Now on to some issues about what makes a lens good. You prefer to shoot
wide open for shallow DOF. That means is that you will almost never see
image corners in focus, so corner sharpness isn't of much concern to
you. Many photographers of landscapes and such subjects want lots of DOF
and sharp corners. Photographers of architecture want all that plus
minimal linear distortion. I can't tell anywhere near for sure, but I
suspect from the sample that this lens has some classic bulgy center WA
distortion.
I'm very happy for you, to have a lens that so perfectly meets your
needs. On the other hand, it is clearly far from perfect and would
almost certainly not be the best lens for many other photographers.
> I have never personally used any wide-angle lens that can perform anywhere
> near this level. Not many 35mm or equiv. lenses, wide-open, will not show one
> bit of chromatic aberration or coma with these bright lights in the corners
> of the frame.
Huh? There's no detail at all, let alone light, in the corners of this
image. Show us some tree branch detail against bright sky in a corner of
a frame if you want to sell that point.
> ... M.Zuiko 17mm, [stinks] ...
>
> This may be ballsy, but I'd like to see if the Leica M Summicron 35mm (a
> non-retrofocus design) can compare,
> for an image of at the same output size. (sure, I know this is medium format,
> but we can still compare relative
> lens performance by "ignoring" capture medium size, it's the output that
> counts, right?).
>
Not necessarily. Depends on the task at hand.
> ... Every time I lust after that OM Zuiko 35mm f/2.0 lens I can't afford
> right now, I am consoled by using this magical lens (which actually cost me a
> lot cheaper than the Zuiko :-).
And here I am, feeling a bit down after reading posted here all the
things wrong with it after I won one. :-)
> Ken, you're the lover of the Zuiko 35mm f/2.8, show us what it can do?
> (relatively speaking)
>
At the moment, I've got both. Just fly me down and I'll try both on your
Cuban restaurant. My 35/2.8 is MC and black nosed, though, so you might
have to fly Ken down with me. ROAD TRIP!!
> <Snip more general praise for Mamiya lenses.>
No offense meant, and I hope none taken. You did throw down the
gauntlet, didn't you?
Moose
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