Medium format versus digital sharpness

"Neil Gould" <neil.TakeThisOut@myplaceofwork.com> wrote:
> Recently, David J. Littleboy <davidjl.TakeThisOut@gol.com> posted:
>> "Neil Gould" <neil.TakeThisOut@myplaceofwork.com> wrote:
>>>
>>> Still, comparing top-of-the-line options would suggest a
>>> professional drum scan (and not a "fake" drum scan e.g. something
>>> like the Imacon).
>>
>> OK.
>>
> http://www.ales.litomisky.com/projects/Analog%20versus%20Digital%20Shootout%20(Hasselblad,%2035mm,%20Canon%205D).htm
>>
> I do like this comparison much better than Rafe's, David, but, it still
> has issues.

It demonstates that 645 and the 5D are rather similar beasts, and that 35mm
is sick by comparison.

Which of 645 and 5D is "better" is an argument that splits hairs far finer
than I'm interested in.

All these make it abundantly clear that 645 and 5D are _roughly_ equivalent.
If you find one of these not good enough for a particular application (e.g.
a 30 x 40 advertising poster that people can walk up to), what you really
need is a larger format or a lot more pixels. The other won't be enough of
an improvement.

That is, 645 is, for all practical purposes, equivalent to 12 or 16MP or so.
645 is "worth" a lot more than 8MP and a lot less than 24MP. (With decent
technique, 645 is always better than 8 and worse then 24MP.)

So 6x7 (having 1.66 times the information of 645) is "worth" a lot more than
13MP and a lot less than 40MP. Which is rather different than QG's 100MP. QG
is off by a factor of four.

> As presented:
>
> * Scanning details would be a good thing, rather than just stating the
> type of scanner. What resolution and optimizations were used to make the
> scan? One can purchase "cheap" professional scans, and one can do poor
> scans on a good scanner, too.

Quibble quibble. Those are quality, professional drum scans.

> * Post-processing adds too many variables for the both digital and film
> workflows. I can see no reason to involve these manipulations in an
> objective comparison.

Those are the standard, agreed techniques for making high-quality
enlargements. But I see your point.

He's playing a similar game to this guy.

http://www.shortwork.net/equip/review-1Ds-SQ-scantech/

That is, they're both making prints that are (in my opinion) way beyond
reasonable for either format.

But that's actually a good way to compare, because the differences are more
visible.

At 12x18 (where I think 645 and the 5D womp 35mm), some people think 35mm
looks great.

At 16x20 (where I think 6x7 womps 645/5D), some people think 645 and the 5D
look great.

> Finally, I don't think that the results support Litomisky's conclusions.
> Even accepting the above issues and just looking at these shots as
> presented raises questions. The image from the 5D has more contrast, but
> loses detail (a condition that is favored by Photoshop's bicubic
> algorithms, btw), as can be seen by comparing interior portions of the
> branches, faces of the leaves, and mortar between the bricks to the
> Hasselblad shot.

He's using Velvia, and the grain is seriously ugly at that enlargement.
Provia 100F wouldn't look so bad, and TMX100 would probably hold a bit more
detail.

> So, I still think that what one thinks is "best" all depends on what one
> wants in an image.

We're in some sort of agreement here: I don't think there's enough of a
difference to call a winner in the 645 vs. 5D fight.

David J. Littleboy
Tokyo, Japan

On Wed, 7 Nov 2007 08:58:56 -0600, "Neil Gould"
<neil.DeleteThis@myplaceofwork.com> wrote:


>The "film" was scanned in all likelihood without a glass film holder, as
>it would have been worth mentioning if it was. My ArtixScan 120tf is
>essentially the same scanner, and there is a *huge* difference in scann
>quality when the glass film holder is used.
>
>Still, comparing top-of-the-line options would suggest a professional drum
>scan (and not a "fake" drum scan e.g. something like the Imacon).


Neil, do you have any scan samples that look substantially
better than those I've posted on my "scan snippets" site?

If you do, I'd love to see them. From your LS-120 or from
any other scanner.

And if you don't, I think there's no other conclusion that
well-scanned 645 matches up pretty well with the output
of a Canon 1Ds or 5D, when the latter are up-rezzed to
match the pixel dimensions of the film scan.

In my experience, a glass holder allows for better
uniformity of focus across a given slide or negative.
But critical focus can be achieved -- at least on a
portion of the film -- without it.


rafe b
www.terrapinphoto.com
scan snippets:
www.terrapinphoto.com/jmdavis