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  Topic: Lou FCD's photo corner, Technics, equipment, photos...< Next Oldest | Next Newest >  
socle



Posts: 282
Joined: July 2009

(Permalink) Posted: April 21 2012,09:52   

Quote (Schroedinger's Dog @ April 21 2012,08:30)
So.... are we having our Lensesgate now?

Ok, ok, just kidding!


  
dhogaza



Posts: 525
Joined: Feb. 2006

(Permalink) Posted: April 21 2012,13:15   

Quote
Using a film like Kodak Technical Pan developed for continuous tone (POTA, 15 minutes at 68 degrees F, no push, no pull, no nothing) that has essentially no shoulder in the highlights makes a transmission difference like the one in the lens mentioned above highly relevant and not something that would be swamped by other parts of the process.


Well, I already pointed out that for film with limited latitude such as Velvia (slide film for those of you who don't know film from artificial cheese food) the difference between a lens' F- and T-stop could be important if they varied significantly.

Tech-Pan (which I enjoyed playing with back in the day) is certainly an unforgiving negative film.  I won't disagree with that.

Indeed, I'd say it's an exception that supports my general point that shooting typical B&W negative film, with its generous exposure latitude, coupled with the freedom one has in the darkroom with developers, paper, etc, makes a 1/2 stop difference in T- and F-stop unimportant.

After all, it is this flexibility that gave rise to the Zone System, which is end-to-end (film choice, exposure, development, paper choice, manipulation while printing, paper development, etc).

Quote
I feel like I've fallen through the rabbit hole to a place where people who I know to value knowledge in other circumstances are suddenly arguing for the primacy of ignorance in this one.


Be careful with that given your response to midwifetoad's point:

Quote
If I select 4.5 (aperture priority), the camera may select a shutter speed somewhere between 1/250 and 1/500. Actually it records the shutter speed in decimal seconds.

If I use shutter priority, the camera uses continuously variable aperture settings.

So It doesn't care what the actual transmission factor might be.


It doesn't care in these auto-exposure modes because it's measuring through-the-lens, it just sees light.  The T-stop will always be less than the F-stop, TTL metering accounts for that.  Slap a 1-stop ND filter on the front, you'll still get a proper exposure.

You don't need to know that the T-stop of your Nikkor 200-400/4 is really closer to F-5, TTL measures the light entering the camera box, it's already taken care of.

You don't even have to worry about the fact that it's very unlikely that the 200-400/4 has an absolutely constant aperture throughout its range but probably varies +/- 5% or so.

Midwifetoad's pointing this out doesn't make midwifetoad ignorant.  Your pointing out the 1/2 stop difference between T- and F-stop in the Nikkor 200-400 just underlies the convenience of TTL metering as described by midwifetoad.

My pointing out that still shooters largely ignore the difference between T-stop and F-stop for a variety of reasons doesn't make me (or the vast majority of professional shooters) ignorant.  My pointing out that T-stop  vs. F-stop is important in traditional cinematography largely because traditionally prints were contact printed from the film negative with no opportunity for frame-by-frame (or scene-by-scene) corrections of exposure doesn't make me ignorant.

Pay attention before accusing me or others of "arguing for the primacy of ignorance".

  
Wesley R. Elsberry



Posts: 4511
Joined: May 2002

(Permalink) Posted: April 21 2012,14:08   

Quote (midwifetoad @ April 21 2012,07:11)
Well we could always convert this into an argument about gnu atheism, but seriously, my comment had a very limited scope. I had no idea I was disagreeing with anything you said.

If you are reviewing lenses on the basis of transmission, you would be lenses of the same type, as in different brands and models.

Incident light metering is rather specialized. It's used in studios and in movie making, but I think anyone going to that kind of trouble would calibrate a system with actual test shots.

Back when shutters were mechanical and involved a moving slit of varying width, it was widely recognized that effective shutter speed didn't necessarily match nominal speed.

And if you developed your own film you noticed differences between brands and types of developer. I read, for example, that National Geographic had all of their film processed in one plant, and did not allow it to be done as the first batch of the day. They wanted assurance that the chemistry was right.

For 99.9 percent of people using digital cameras, these issues are irrelevant, even if interesting. I would bet not many people shooting RAW images would notice half an f-stop difference in exposure. In fact people routinely adjust the levels in their photos to make them "pop."

This can easily truncate several f-stops of shadow and highlight detail.

I think I'm getting to where I understand how my experience of your comment differed so completely from how you perceived your comment. At least part of the utility of the concept of f-stops is universality, a metric that applies to all lenses and light-passing gizmos. It allows comparison. Your comment, though, with the "irrelevant" phrasing looked to me that it simply assumed that comparison itself was not an issue of interest, and only use of a specific lens with a specific camera feature mattered.

That other parts of a photographic system have slop in them is not a reason to bypass understanding of one particular part. Nor do I find polling useful in determining whether to pay attention to and learn a technical topic. Most people don't have a clue about genetics and no demographically broad practical need to know more; should we discourage learning about the technical details as "irrelevant" there?

Let's look at what you say about comparison here:

Quote

If you are reviewing lenses on the basis of transmission, you would be lenses of the same type, as in different brands and models.


This is, again, much too glib.

One can easily have a comparison among multiple lenses in the same brand. Nikon makes and has made quite a variety of 85mm short telephoto lenses. The second link from my last message shows an example of a run of Nikkor 85mm lenses whose multi-coating is particularly ineffective. If one buys lenses used, knowing about this difference could result in one buying a better, higher-transmission lens from later in production. That would be a case of same brand, same model, and same marked f-stop. Or choosing which particular 85mm model to buy could involve a tradeoff between the actual light-transmitting characteristics and one's pocket-book. This isn't a simple function of adding a constant to the f-stop of all the choices.

Nor does the restriction of "same type" necessarily hold. One might choose between a zoom lens and a prime lens for a job based on light transmission. Whether one makes that decision might well be influenced by whether the circumstances permit the difference in T-stops between the two rather than f-stops. For concert photography, an additional T-stop difference as opposed to the marked f-stop difference might well tip the balance in favor of the prime lens, where the marked f-stop difference might have been an acceptable tradeoff for the convenience of the zoom, but the T-stop difference would not be.

Of course, f-stop versus T-stop is just one of many factors that would go into a lens purchase or use decision, but given the hard constraints of available light photography, it is one that will continue to engage -- and reward -- photographers looking for the very best results.

Automatic systems help produce passable results for lots of people. The Kodak Brownie camera was a huge hit in the late 1800s because it allowed people to use photography without all that difficult mucking about with picking exposure times and such-like. The fact that Brownie technology existed did not obviate the knowledge garnered by people who chose to keep on with their view cameras and glass plates. Nor do the very much improved automatic systems of today render knowledge of systems under physical constraints "irrelevant". If you only have one lens (or one lens per activity) and you simply rely on automation, conceptually it doesn't make much difference whether the camera you use is called a "Canon 5D MkII", "Nikon D700", "Holga", or "Kodak Brownie".

It's a difference between knowing your tools and "Whatever". A lot of people can (and do) get by with "Whatever", but anyone who has come away with a blurry mess where they had visualized a sharp decisive moment may well want to reconsider adherence to "Whatever" as a photographic learning strategy.

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"You can't teach an old dogma new tricks." - Dorothy Parker

    
fnxtr



Posts: 2152
Joined: June 2006

(Permalink) Posted: April 21 2012,14:43   

Barkingside!

Oh, wait, this isn't the MC thread?

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"But it's disturbing to think someone actually thinks creationism -- having put it's hand on the hot stove every day for the last 400 years -- will get a different result tomorrow." -- midwifetoad

  
Wesley R. Elsberry



Posts: 4511
Joined: May 2002

(Permalink) Posted: April 21 2012,15:00   

Dhogaza, Speaking of paying attention, I explicitly stated that no one here had at any time denied the ability of an autoexposure system to do its job. Acting as though that were a live issue isn't productive.

Nor have I accused midwifetoad or you of being ignorant of the f-stop versus T-stop distinction (or how automation functions, for that matter). What I'm objecting to is what looks to me to be encouraging others who may not know it from even considering learning about it. And I realize that that may simply be an unintended consequence of a particular word choice in that original comment by midwifetoad that has cascaded. But there have been errors committed as well, what with the mention of autofocus as not being affected by T-stop issues and the spurious restriction on how broadly comparison might be touched by that issue. The same tendency to correct invalid claims about evolutionary theory underlies my drive to correct what I perceive to be problems in claims about other topics I know something about.

And that brings us to the Zone System. The Zone System works by systematically removing the uncertainty from the equipment and processes going from film to print. There is a lot of flexibility inherent in that, but the Zone System relies upon calibration so that each element of flexibility becomes characterized and the response to perturbation can be utilized under the control of the photographer. That includes the actual light transmission characteristic of any lens used. The Zone System does not make a difference between marked and actual transmission unimportant, it makes it well-characterized and part of the control of the process that is the photographer's responsibility.

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"You can't teach an old dogma new tricks." - Dorothy Parker

    
dhogaza



Posts: 525
Joined: Feb. 2006

(Permalink) Posted: April 22 2012,23:16   

[QUOTE]Dhogaza, Speaking of paying attention, I explicitly stated that no one here had at any time denied the ability of an autoexposure system to do its job. Acting as though that were a live issue isn't productive.[/QUOTE>

Earlier:

Quote
If you are using TTL autoexposure, that will (mostly) work out


That little word "mostly" indicates that you *can't* depend on TTL to measure T-stop vs. F-stop.  You explicitly state that it can't always do its job regarding differentiating F-stop from T-stop.


"(mostly)" is semantically equivalent to "not always".

Which is bullshit.

Now one can argue whether or not in-camera exposure systems can be as accurate is external metering systems, but that was not your argument.  But what ever errors internal metering systems make, they are based on T-stops, not F-stops, and the difference does not contribute to the error.

We could, of course, talk about the very many external incident meters that were produced in the 1930s, 40s, 50s, 60s that were such crap that their crappness swamped any difference between F-stop and T-stop or film speed or whatever.

Continue to box yourself in, I'm enjoying this.

  
dhogaza



Posts: 525
Joined: Feb. 2006

(Permalink) Posted: April 22 2012,23:22   

Quote
Nor have I accused midwifetoad or you of being ignorant of the f-stop versus T-stop distinction (or how automation functions, for that matter). What I'm objecting to is what looks to me to be encouraging others who may not know it from even considering learning about it.


If this is truly your intent, rather than insulting someone who knows at least as much about photography as you, well ...

You're still wrong.

Modern digital photography combined with modern lenses combined with TTL exposure means you can, and should, ignore T-stop differences from F-stops.

With the 14-stop latitude modern digital cameras yield compared to the 7-stop latitude (more or less) offered by various printing technologies, you can just fucking forget 1/2 stop T-stop vs. F-stop differences, even if you meter externally.

And with modern digital cameras, internal metering is just fine.

Look, it was hard for me to trust my meter when I switched to digital and started to realize I could squeeze 14-stop latitude out of an exposure vs. the 5.5-stop or so out of chrome.

Because I realized I didn't have to be as anal about exposure as I was before (and look, I was *good* at it, selling chrome to magazines and book publishers world-wide as a side-line).

Kinda made me feel that those skills I learned were ... unimportant.

But underneath, I understood that the power of compositon, lighting, timing etc were what's really important, and if I don't need to agonize over Tech Pan's unforgiving shoulder ... that's a blessing.

  
dhogaza



Posts: 525
Joined: Feb. 2006

(Permalink) Posted: April 22 2012,23:30   

<blockquote>The Zone System does not make a difference between marked and actual transmission unimportant, it makes it well-characterized and part of the control of the process that is the photographer's responsibility.</blockquote>

It makes it very much unimportant as straight-print vs. highly-manipulated prints of Adams' photographs (such as that posted by me for "moonlight") make clear.

Crap, dude, the spring-loaded (vs. electronically timed of today) shutters were relatively flakey.

Not to mention the relatively primitive meters Adams used.

You can see from the before and after prints of "Moonlight" that Adams killed most of the dynamic range in the negative.

His T-stop vs. F-stop could've been 2 or 3 stops and he could've come up with a nearly identical image.

And, yes, I'm one of those who does not believe AA was god.

  
Lou FCD



Posts: 5379
Joined: Jan. 2006

(Permalink) Posted: April 23 2012,06:18   

Questions into the wind:

How much post-processing (Photoshop, for instance) is too much? Where do you draw the line (if you do)?

I don't mind softening the focus a bit to play down a few years' worth of age, or zapping an unfortunate pimple, but I won't use something like liquefy to slim a hip, for instance. It's probably a completely arbitrary and subjective line, but it's mine, damnit. What's yours?

What software do you like, and why?

I'm using Digital Photo Professional (comes standard with a Canon) to sort through and do mass deletions, and maybe take a quick peek at the shots. I like the interface for selecting a group of shots, looking at them in the edit window to decide which I'm going to keep, and deleting the rest.

But for the actual post-processing, I'm using Lightroom 3. I like the controls and the end-product, but sometimes I look at some really great photographers' work and wonder if I'm missing some critical piece of software, or if its just a matter of experience.

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Lou FCD is still in school, so we should only count him as a baby biologist. -carlsonjok -deprecated
I think I might love you. Don't tell Deadman -Wolfhound

Work-friendly photography
NSFW photography

   
midwifetoad



Posts: 3587
Joined: Mar. 2008

(Permalink) Posted: April 23 2012,06:32   

Must be pollen or something making people edgy on the net this week.

I have no interest in fighting over misunderstandings of intended meaning.

I would like to add, though, the observation that when i look at the levels in my digital photos, most do not use the full dynamic range. I wind up effectively bumping up the contrast.

Thi is especially true when shooting RAW, where the tools allow you to adjust the dynamics without losing highlight and shadow detail.

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lets not make a joke of ourselves.

Pat Robertson

  
Freddie



Posts: 366
Joined: Oct. 2009

(Permalink) Posted: April 23 2012,08:56   

Quote (Lou FCD @ April 23 2012,06:18)
Questions into the wind:

How much post-processing (Photoshop, for instance) is too much? Where do you draw the line (if you do)?

I don't mind softening the focus a bit to play down a few years' worth of age, or zapping an unfortunate pimple, but I won't use something like liquefy to slim a hip, for instance. It's probably a completely arbitrary and subjective line, but it's mine, damnit. What's yours?

What software do you like, and why?

I'm using Digital Photo Professional (comes standard with a Canon) to sort through and do mass deletions, and maybe take a quick peek at the shots. I like the interface for selecting a group of shots, looking at them in the edit window to decide which I'm going to keep, and deleting the rest.

But for the actual post-processing, I'm using Lightroom 3. I like the controls and the end-product, but sometimes I look at some really great photographers' work and wonder if I'm missing some critical piece of software, or if its just a matter of experience.

That's a good question.

I shoot RAW + Fine JPG, then dump them all onto the PC and decide which images to keep by looking at the JPGs in Windows Photo Gallery. I find I can weed out the poorer images more quickly this way: delete the JPGs then go through and delete the RAWs that have no corresponding JPG in the folder.

Then I use Photoshop Camera RAW v6 for lens correction, straightening and cropping, then open up the resulting image in PS CS5 for editing (I know you can do a lot more in Camera Raw as well but I'm more familiar with CS5 having used Photoshop for about 10 years now).

Using Camera Raw as input to Photoshop I think provides a better result than DPP --> Photoshop, as DPP can only save to JPG whereas Camera Raw uses TIFF as the intermediate file format (and Photoshop cannot open DPP files directly).

I'll usually do no more than sharpen, colour correct and adjust the dynamic range on the image using the unsharp mask, Curves tool and layer blending respectively, although I have been known to clone out the odd pimple here and there if it's only a 'temporary' feature (or clone out a bird from an otherwise flawless sky or similar etc.) I don't think i'd ever want to materially change an image such that it doesn't represent what I actually shot but I have no qualms about using Photoshop to realize different versions of the same image.

More recently, i've been using the Shadows/Highlights tool in CS5 instead of layer blending. It can provide some fantastic results for images that have difficult exposures (or just poor ones like this off-the-cuff shot I took in Rome last week).

One item I would like to have is a better screen. I have a 'standard' Samsung 22 inch LCD which is calibrated by eye/free tools only. It would be nice to have a really decent screen properly calibrated for this type of work but out of my price range right now.



"Late afternoon sun at the ice cream parlour, near the Fontana di Trevi"

[ETA: Just to make it clear, the top image is the JPG off the camera, the bottom is the manipulated RAW image.  If there was no RAW I would have been stuck trying to fix the overexposed JPG which is never easy!]

--------------
Joe: Most criticisims of ID stem from ignorance and jealousy.
Joe: As for the authors of the books in the Bible, well the OT was authored by Moses and the NT was authored by various people.
Byers: The eskimo would not need hairy hair growth as hair, I say, is for keeping people dry. Not warm.

  
midwifetoad



Posts: 3587
Joined: Mar. 2008

(Permalink) Posted: April 23 2012,09:50   

It's pretty amazing what you can do with highlight and shadow detail when shooting RAW.

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lets not make a joke of ourselves.

Pat Robertson

  
Dr.GH



Posts: 1966
Joined: May 2002

(Permalink) Posted: April 24 2012,12:47   

Quote (Wesley R. Elsberry @ April 20 2012,05:38)
I gave my last Nikon F to a friend, but I still have an F2 and a Beseler 45MX.

I love my Beseler, and have kept it even without a darkroom for the last 15 years. (Some day I'll get another darkroom! Really.)

I also still have my old Pentax magazines, and screwmount lenses. Illford, and Fuji still make film (don't they?). Maybe they are all just door stops now.

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"Science is the horse that pulls the cart of philosophy."

L. Susskind, 2004 "SMOLIN VS. SUSSKIND: THE ANTHROPIC PRINCIPLE"

   
Dr.GH



Posts: 1966
Joined: May 2002

(Permalink) Posted: April 24 2012,12:54   

One totally off-the-cuff use I made of f-stops was using them as a buying guide for lenses. The cheaper lenses needed to be stopped way down because their glass, and crappy polishing  distorted images on the edges. The wider the aperture you could use, the better the glass- the better the lens.

--------------
"Science is the horse that pulls the cart of philosophy."

L. Susskind, 2004 "SMOLIN VS. SUSSKIND: THE ANTHROPIC PRINCIPLE"

   
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