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Thursday, 28 August 2008


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Years ago, Pop Photo ran a story about lens test charts. They said the most complaints were that lenses were meant to take photographs of actual scenes, not test charts. So they took two lenses, a Leica 50mm and a so-so 50mm, and photographed a billboard across the street. The Leica was clearly superior. I could see the softness of the so-so lens. That's the real test - the real world.

Just my .02...

Have used Canon since 300D. Now use 20D and 30D for weddings with "L" lenses. Had to do a job needing time lapse sequencing and found Pentax K100D to be only camera around which shuts down to micro-amps in "stand-by" mode- most others only milli-amps, thus using much more power from batteries. JPEG quality was OK, but contrast high in some shots. Comes the 200D - bargain of the century- fantastic quality with Sigma zoom at f8- straight JPEGs amazingly good. Used a Super Multi-Coated 50mm f1.4 off my old K1000 in a few test shots and the quality was simply astounding. Would love to try some of the wonderful Pentax "created-for-digital" lenses, but am very happy with the existing K200 images from my time-lapse sequences. The camera is at the top of a fixed pole at present for the next two months, but I'd love to try it at a wedding next week and compare the image quality with my Canons. My first ever great camera was a Pentax SV in 1967 with attached Mk1 CDs meter above prism. It finally went to the great Pentax graveyard in the sky in 2004 with absolutely no servicing and thousands of films under its belt.

I couldn't vote on my Linux box, but I did figure out which one was f/5.6, and was surprised most people got that wrong. I was way wrong on f/2.8 though.

This was pretty neat, showing that even though most apertures were correctly identified, not all of them were, and furthermore, *many* people were incapable of discerning apertures correctly. I wonder if anyone identified all of them; maybe Salviano has the data on that.

I think there is an important parameter that also affects lens reviews, and that is sample variance. Pentax seem to have had a problem with lenses such as the DA* 16-50mm, but even when lenses are "within specs" there will still be variations between units. Who was that Canadian photographer that would keep going back to the camera store until he got a perfect sample of a lens?

I'm sure battles will continue to rage across the Net, but at the end of the day it's all about opinions and expectations.

I did the test, first.
Mostly to confirm something me myself and I
have been battling for some time.
And I was correct. Mostly.
I chose number 6.
Now keep in mind I use a 14 inch screen on
a Macintosh iBook laptop. Not the best viewing
screen however it has done me well for many years.
And it also proves to me that I really don't
care two hoots one way or the other about
aperture or anything else.
As long as the picture looks good, whatever it may be that's OK too.

As I may have mentioned in an earlier note
have spent all too much money looking for
the ideal?/best? digital image capture
machine. I think I've spent almost C$5000.00
on D100's, D200's, a D50 and a D80 to come
to the simber realization the D40 the 6.1 mp
D40 is about my speed. And, even that camera
is difficult to master, for me.

Back to the basic film for me? Maybe.

Bryce Lee
Burlington, Ontario
Canada, eh?

"Now keep in mind I use a 14 inch screen on
a Macintosh iBook laptop. Not the best viewing
screen however it has done me well for many years."

I never realized how bad the iBook screen was until I got a MacBook Pro. All of a sudden I realized WHY my photos lacked sharpness and contrast. The difference was shocking. The iBook screen is awful, but you don't realize how much until you get a better one.

Shhh...you'll remind me how long it took me to accommodate to the screen of the 20" iMac. Truth be told, I still miss the CRT screen in my old eMac, which was much better and nicer to look at (and easier to match to prints, subjectively anyway).

Mike J.

Why am I unsurprised that this post has only attracted (as of the time I posted this) six comments, whereas hecklers are eager to post hundreds of derisive comments whenever they feel that their camera/lens brand of choice has been maligned, or a competitor's product unjustly praised (especially if the criticism/praise is based on "unscientific" tests)?

BTW, for an excellent example of what I'm talking about, go to DPReview and check out what Nikon fans are saying about the Canon 50D, and what Canon fans are saying about the Nikon D90. People are comparing the image quality of unreleased cameras based on language in press releases!

Then again, press releases are clearly scientific, so it is hard to argue with the facts, right?

"Truth be told, I still miss the CRT screen in my old eMac, which was much better and nicer to look at (and easier to match to prints, subjectively anyway)."

Mike, this is why I maintain my trusty CRT Sony 19". Ordinary LCD can't match it for viewing photographs.

I might add I did purchase a wide screen
iMac, used; some months ago.

I have been using the iMac machine for my photo review work.

However even though it could be considered
a tradtional desktop computer,I still much
prefer the iBook G4.

Suspect it is convenience.

One point I believe all using a screen
for reviewing images should keep in mind
is technology keeps changing and the methods
by which we use the technology.

Compare a current digital image viewed on
that iBook to say the eMac or even the
original iMac! There is a difference.
Often wonder with my aging eyes if what
I am viewing is what I want to see
rather than what is actually there, on screen.

Bryce Lee
Burlington, Ontario

Hi Miserere, I haven't the individual data. I published all the results on the page. For the six apertures, only two were correctly identified. There are one aperture (f/16) with virtually equal distribution of answers.

One guy complained because I used a different amount of fine-tuning sharpening. My thought is, everyone will search for the best sharpness setting for each individual file.

But to do the things more clear, I redid the test (2nd round) with the SAME amount of sharpness. I don't see any important difference, but I will invite the people to do the 2nd round. I have no reason to believe, this time *many* people will find the right apertures.

Yes, I agree. I experienced a slightly decentering in one zoom lens, but only discovered when performed a "playing cards test chart" like this. The funny thing is, probably I never knew if not tested.

There are other important parameter that *not* affects lens reviews, but affect "users". It's about focus. It's a public info, that they have been taking lots of photos of the charts and selecting the best one of the series to run the graphs.

Quote from a reviewer: "We've come to say around the lab that the actual performance of modern AF systems is the "dirty little secret" of the camera industry."
Autofocus, Manual Focus, or focus through live view is not reliable. The only solution suggested to measure the MTF, is focus bracketing. There's a interesting reading here http://www.slrgear.com/articles/focus/focus.htm

Now, imagine the craziness of the thing: How many phtotographers in the world will intend to perform a millimetrec focus bracketing? For 100% of the scenes with even a slight movement, it's simply impossible to do that. For static scenes is 99% unpractical.


Salviano Junior
Rio de Janeiro

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