Please check this...

Juan Valdenebro

Juan Valdenebro

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Hi,


To see how my new old Leica 90mm Summicron behaves opened and closed (how much real change in DOF, IQ and contrast) I went into one of those geek tests we geeks do...


One of the scenes, this superb sculpture showing Pau Casals enjoying (classic rusted dark green metal) was shot under overcast sky, handheld with Neopan1600 in Rodinal 1:50, and originally scanned at 4800 dpi (lots of pixels per grain). Focus was on his left hand fingers from four meters distance. All shots were treated the very same way in scanning and Photoshop (by the way, no scanner or Photoshop Unsharp mask at all). As they were well exposed, I just gave them a bit of blacks to get them pure in some place, but no contrast slider up, so to retain real lens' blur...


Depth of field is really narrow, and I like the lens: old and relaxed looking...


Now the question. I see by the right bottom corner, shadows become deeper by f/5.6 as a result of increased focus: normal. What surprises me is that, contrary to this, comparatively with the more opened shots, on the same f/5.6 image there's less contrast in other places, like below his left hand and on his face, neck and bow tie...


I had never been conscious of this before... Is this apparent contradiction normal? Why does it optically happen?


Thanks.


http://www.flickr.com/photos/40894234@N07/4036372691/
 
ok here's what i see:
1. the four shots are not exposed the same way(or not scanned the same way).
They are increasingly more exposed towards the right (towards f/5.6).
I have a theory on this. Since more sky is included in the f/2 shot (you poiunted the camera higher! or you cropped the shots?), the exposure meter (either from camera or scanner) was adjusting exposure i.e. decreasing for f/2, increasing for f/5.6

2. Why would you "test" sharpness related stuff handheld and with an iso 1600 film? If you want to do real geeky tests 🙂, do it properly, use slow film and use a tripod.

greetz
 
ok here's what i see:
1. the four shots are not exposed the same way(or not scanned the same way).


EXPOSED AND SCANNED THE SAME WAY. HANDHELD INCIDENT METERING ONLY: LIGHT DIDN'T CHANGE (ANYWAY METERED BEFORE EVERY SHOT)


They are increasingly more exposed towards the right (towards f/5.6).
I have a theory on this. Since more sky is included in the f/2 shot (you poiunted the camera higher! or you cropped the shots?), the exposure meter (either from camera or scanner) was adjusting exposure i.e. decreasing for f/2, increasing for f/5.6


WRONG, AS YOU SEE, BUT THANKS... (BESSA T HAS NO AE, AND I DON'T USE AE EITHER)

2. Why would you "test" sharpness related stuff handheld and with an iso 1600 film? If you want to do real geeky tests 🙂, do it properly, use slow film and use a tripod.


THE TEST WAS FOR DOF GAIN, NOT SHARPNESS, WHICH IS OF LITTLE IMPORTANCE... ANY FILM IS GOOD ENOUGH FOR THAT. ANYWAY, YOUR WRONG ANSWER WASN'T EVEN ANSWERING THE QUESTION ON TWO DIFFERENT AND OPPOSITE LOCAL CONTRAST VARIATIONS.



YOU COULD TRY AGAIN...🙂

CHEERS,

JUAN
 
OK here i try again:
1. Why all capitals?
2. I don't know what you used and i don't care. I didnt say your metering was surely wrong, it was just a theory of what COULD have happened (i tried not to blame you but the circumstances).
I said it was differently exposed. This can come also from not-exactly f/2 aperture or the shutter times not-exactly matching what they should be.
Fact is: on the monitor the f/2 image is darker EVERYWHERE than the f/2.8, which is darker than the f/4 which is darker than the f/5.6. The sky is darker, the midtones are a bit darker, the shadows are darker.
If you don't see this, then i can't discuss anything further.
3. "on the same f/5.6 image there's less contrast in other places[...] is this apparent contradiction normal?" I thought this was the essence of your question, i apologize if it was not. Looks like less contrast becuase it's just brighter, as i wrote.
4. Judging "DOF GAIN" (whatever that is!) depends also on your starting point, i.e. how sharp is your in-focus image part. How can you judge "DOF GAIN" if your sharpest regions are compromitted by motion blur or 1600 speed film unsharpness?

You can say whatever you want but sharpness related issues (yes DOF is SHARPNESS related) are NOT done handheld on high speed film because there are too many factors to influence your decision, it's not just me who decided this, it's common sense. In addition, you asked for answers, i answered with only good intentions, so your somewhat arrogant reaction is a bit of a surprise.

Here. I tried again. Winner this time? What did i win?
 
You need a nice sharp contrasty 8.5cm f/2 Nikkor. You'll get more depth of field than with a 90 'cron of any vintage. Have you tried wet printing the negative? The natural H&D curve of the paper might give you what digital's linear response in lacking.
 
Pherdinand said:
OK here i try again:


1. Why all capitals?
2. I don't know what you used and i don't care. I didnt say your metering was surely wrong, it was just a theory of what COULD have happened (i tried not to blame you but the circumstances).
I said it was differently exposed. This can come also from not-exactly f/2 aperture or the shutter times not-exactly matching what they should be.
Fact is: on the monitor the f/2 image is darker EVERYWHERE than the f/2.8, which is darker than the f/4 which is darker than the f/5.6. The sky is darker, the midtones are a bit darker, the shadows are darker.
If you don't see this, then i can't discuss anything further.
3. "on the same f/5.6 image there's less contrast in other places[...] is this apparent contradiction normal?" I thought this was the essence of your question, i apologize if it was not. Looks like less contrast becuase it's just brighter, as i wrote.
4. Judging "DOF GAIN" (whatever that is!) depends also on your starting point, i.e. how sharp is your in-focus image part. How can you judge "DOF GAIN" if your sharpest regions are compromitted by motion blur or 1600 speed film unsharpness?

You can say whatever you want but sharpness related issues (yes DOF is SHARPNESS related) are NOT done handheld on high speed film because there are too many factors to influence your decision, it's not just me who decided this, it's common sense. In addition, you asked for answers, i answered with only good intentions, so your somewhat arrogant reaction is a bit of a surprise.

Here. I tried again. Winner this time? What did i win?
Click to expand...

HEY, COOL DOWN!

I APPRECIATE YOUR EFFORT, REALLY. IT'S NOT ARROGANCE, LET'S GO AGAIN:

1. Why all capitals?

DON'T WORRY, IT'S NOT BECAUSE OF ANOTHER PHOTOGRAPHIC REASON YOU DIDN'T CATCH 🙂, IT WAS AND IS TO MAKE YOUR TEXT AND MINE (EVEN MORE) DIFFERENT. IN MY CAPITAL OPINION THAT COMMENT WAS NOT NECESSARY (EITHER).

2. I don't know what you used and i don't care.

YOU SHOULD, BECAUSE YOU ANSWERED BASED ON AUTOEXPOSURE. YOUR CASE IS NOT THE CASE OF ALL OF US.

I didnt say your metering was surely wrong, it was just a theory of what COULD have happened (i tried not to blame you but the circumstances).

NEVER FELT YOU BLAMED ME!

I said it was differently exposed. This can come also from not-exactly f/2 aperture or the shutter times not-exactly matching what they should be.
Fact is: on the monitor the f/2 image is darker EVERYWHERE than the f/2.8, which is darker than the f/4 which is darker than the f/5.6. The sky is darker, the midtones are a bit darker, the shadows are darker.
If you don't see this, then i can't discuss anything further.

WHAT YOU SEE IN THE SKY, IS THE MOVEMENT OF A CLOUD, AND AS I TOLD YOU, BEING OVERCAST, IT DIDN'T CHANGE ONE TENTH OF A STOP ON MY SEKONIK. BUT MORE IMPORTANT: HAD IT CHANGED, THE QUESTION REMAINS THE SAME, AND IT WOULD NOT BE THE REASON FOR WHAT'S CLEAR: LESS CONTRAST WHEN CLOSING, GRADUALLY. BUT LIGHT AND EXPOSITION WERE THE SAME. WE AGREE: LOOKS LIKE WE DON'T MAKE AN APPROPRIATE DISCUSSION COUPLE, BUT MAYBE IN SOME TIME...

4. Judging "DOF GAIN" (whatever that is!) depends also on your starting point, i.e. how sharp is your in-focus image part. How can you judge "DOF GAIN" if your sharpest regions are compromitted by motion blur or 1600 speed film unsharpness?

HERE YOU'RE CONFUSED AGAIN. SHOTS WERE AT 1/2000 AND 1/1000, AND THEY DO SHOW LENS SHARPNESS. AND OF COURSE NEOPAN1600 CAN BE SHARP! EVEN BY F/2, FINGERS ARE TACK SHARP, AND HEAD IS NOTORIOUSLY OUT OF FOCUS! DEPTH OF FIELD GAIN IS WHAT HAPPENS WHEN YOU USE A SMALLER APERTURE!

You can say whatever you want but sharpness related issues (yes DOF is SHARPNESS related) are NOT done handheld on high speed film because there are too many factors to influence your decision, it's not just me who decided this, it's common sense. In addition, you asked for answers, i answered with only good intentions, so your somewhat arrogant reaction is a bit of a surprise.

AS I TOLD YOU IN THE PREVIOUS ANSWER, THANKS FOR YOUR GOOD INTENTION. I WAS JUST JOKING A LITTLE BIT AS WHEN YOU SAID I SHOULD DO MY GEEK TEST WELL DONE, IT WAS FINE... WHAT IS TRUE IS THAT YOU'RE WRONG IN LOTS OF THINGS. I JUST ANSWER YOU AGAIN BECAUSE THIS IS A PUBLIC PLACE, BUT IF YOU SEND ME A PM, OF COURSE I WOULDN'T WASTE MY TIME TRYING TO EXPLAIN YOU ALL THIS... SO PLEASE DON'T ANSWER AGAIN WITH THE SAME ARGUMENTS: MAYBE I'M NOT THE ONLY INTERESTED IN UNDERSTANDING THE REASONS FOR THIS CONTRAST ISSUE...

Here. I tried again. Winner this time? What did i win?...

COME ON, PHERDINAND, LET'S FOCUS ON THE SUBJECT...

...

Well, I suppose maybe it has some relation with lens design and the way close and background objects are rendered when aperture changes... Anyway I've never heard, seen or read on this...

Maybe the real experts around...? Brian, ferider, Mr. A?

Thanks all for any theory...

Cheers,

Juan
 
Al Kaplan said:
You need a nice sharp contrasty 8.5cm f/2 Nikkor. You'll get more depth of field than with a 90 'cron of any vintage. Have you tried wet printing the negative? The natural H&D curve of the paper might give you what digital's linear response in lacking.
Click to expand...

Hi Al,

I have not tried printing it yet... You must be right on that 85! I use the 105 2.5 and although I haven't done direct comparison shots with the 90 Summicron, I think I remember the 105 isn't that narrow, even when the 90 is closed down some stops... Anyway I'm very happy with it as a new portraiture tool... And it's been my first Leica toy ever! One of these days I should compare contrast and color with slides using the 90, the 105 and the 150 Sonnar... I'm just too busy these days... You're right: when scanning (or at least with my poor scanning) we can't see the same we see after wet printing...

Cheers,

Juan
 
Juan Valdenebro said:
HEY, COOL DOWN!

I APPRECIATE YOUR EFFORT, REALLY. IT'S NOT ARROGANCE, LET'S GO AGAIN:

1. Why all capitals?

DON'T WORRY, IT'S NOT BECAUSE OF ANOTHER PHOTOGRAPHIC REASON YOU DIDN'T CATCH 🙂, IT WAS AND IS TO MAKE YOUR TEXT AND MINE (EVEN MORE) DIFFERENT. IN MY CAPITAL OPINION THAT COMMENT WAS NOT NECESSARY (EITHER).

...
Click to expand...

Hi Juan,

In internet communication, typing in all caps indicates that one is shouting. Since these fora provide a host of text formatting tools, such as italics, color and the ubiquitous 'quote' command, there are much better ways of indicating who says what than by using all caps. In addition to the appearance of shouting, reading sentences in all capital letters is difficult because the start and stops are not so easy to distinguish.

Hope this helps!
 
Hi Juan,

attached a comparison of histograms of the 4 pictures. You can see how the contrast slightly increases across the board when going from f2 to f5.6.

Hope this helps,

Roland.
 
I hope out there some of you are seeing what I see on my two monitors and on the digital print I got today:

There's a contrasty bow tie at f/2, and it goes losing contrast gradually until f/5.6...

Even stranger after general slight overall contrast increase on Roland's curves!
 
I think there's some importance here... If it happens to be as it can be seen, we could say that this lens is more suited to be shot by f/4 or f/5.6 on direct sun for better contrast control on close subjects (portraits), instead of shooting it wide open... And the contrary, wide open, on soft light days...

For example, I see a better portrait on the first shot, with the focus on his fingers and cello and his face a bit away (out of focus) with the music AND the higher contrast in the bow tie.

There must be a reason for this to happen, I mean optically...

But if no one sees it or has any idea why, I won't insist anymore, and just let it go.

Cheers,

Juan
 
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