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05-10-2009, 06:27 PM   #61
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yeah, all the lens purchases add up rather quickly....choice is paralysing but sometimes I'm thankful for the collection of lenses my family has accumulated over the past 60 years

05-10-2009, 08:21 PM   #62
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QuoteOriginally posted by rparmar Quote
Look through the viewfinder with the FA43 on the camera and then look out at the world. Your eye does not need to adjust at all. The size of shapes and the angles you see match up perfectly.
Angles *always* match unless you're using a fisheye - focal length doesn't affect perspective or any other laws of physics. As for size, that's a function of viewfinder magnification. With a K20D or K20D, you need a 55mm lens (or so) to get 100% magnification. With a K200D or K-m, you need more like a 60-70mm lens, because viewfinder magnification is less.

QuoteQuote:
That's what makes it the most natural focal length.
Well, the fact that sizes match on cameras of with a given viewfinder magnifications is an oft-cited reason why a certain focal length might be the most "natural". But given that a different camera with a different viewfinder magnification will provide a different "natural" focal length in this same sense, it becomes clear why this is a fallacy - why should the magnification of the viewfinder - which has no bearing on the final image - have any bearing on the question what is the most natural focal length?

As I said, if you do a search for the topic, you'll find hundreds posts in long rambling discussion on this topic. Lots of interesting facts , theories, and fallacies involved, but it most definitely does *not* boil down to anything simple and objective like this. The concept of what constitutes a "normal" lens is actually a much larger and more maddeningly subjective subject.

The most rational definition I know of involves the idea of producing a print and then viewing the print at a "typical" distance for that size of print, then comparing the angle of view taken up by the print to the angle of view represented by the scene it depicts. For "typical" print sizes, something in the general vicinity of a 50mm lens (on FF) produce the best match, but that doesn't really hold for smaller or larger prints, and in any case, it's just a sort of rough approximation - who is to say what a typical viewing distance is?

QuoteQuote:
The mystery is that this is the same on film or the cropped sensor. The FA43 is a perfect fit for the eyes on both, even though it is not normal on APS-C. I mentioned this on another thread but no-one has been able to explain why it is so.
It's not really mysterious at all once you realize it is all about viewfinder magnification. To the extent that is true, it holds only if you happen to be comparing cameras of the same viewfinder magnification. The K20D has viewfinder magnification of 96% when measured with a 50mm lens. That means you'd need about a 55mm lens to get 100% magnification, like I said. So the FA43 should be noticeably smaller than life size - maybe around 90% or so. Close enough that you might not notice the discrepancy if you weren't looking for it. With a film camera that also provided 96% magnification at 50mm, you'd see the same thing - an image that is a little smaller than life size.

As for angles, again, get out a protractor if it helps, but I guarantee they don't change no matter what focal length you use. Perspective is a function of distance to subject only, not focal length.

Framing is of course *entirely* different between FF and APS-C. The same 43mm lens produces *wildly* different pictures because of the change in FOV. So the idea that you can can just lift the camera and snap with either camera is certain a fallacy - sure, you *can*, but you'll get totally different results. So if you believe that one of them matches your mental framing of the scene, you have to accept the other does not come close. As for what constitutes yur mental framing of the scene, that again is of course entirely subjective. The actual FOV we can take in is *MUCH* larger than 43mm worth - it's somewhere around 15mm or so on APS-C. But some of that is "peripheral", of course. There is no single ahrd and fast line between what constitutes peripheral versus non-peripheral, though. I find the 43mm on FF (28mm on APS-C) sdoes often capture *something* about how I perceive a scene - the part I am focusing one plus the parts I might be able to describe in some detail if questioned. 43mm on APS-C captures more like just the part I am focusing on. But even then, that focus is performed in part with rapid eye movements across the field. The amount of a scene our eyes can actually focus on in any single moment is much narrower - more like the FOV of a 100mm lens on APS-C.

Last edited by Marc Sabatella; 05-10-2009 at 08:29 PM.
05-10-2009, 11:25 PM   #63
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"That's what makes it the most natural focal length."

yeah, my 300mm f/6.3 lens is a more natural FOV on my 8X10...... hehe
05-11-2009, 12:08 AM   #64
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Brilliant post Marc

You are a wealth of knowledge and express well in laymans terms


Cheers


Neil

05-11-2009, 03:20 AM   #65
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QuoteOriginally posted by Marc Sabatella Quote
Supposedly, shmupposedly. There is no "perfect" focal length.
Supposedly, indeed. I didn't write "perfect focal length." I wrote "``perfect''" (the quotes indicating ambiguity and arbitrariness) for a "normal" lens, a word that has a specific (however arbitrary) meaning in the given context. I concluded with the somewhat contradictory implication that for a wildlife enthusiast a starter (and perhaps the only lens) would be in the >300mm range. I hope that clarifies my post and removes at least some ambiguity that may raise ire--in particular, I made no actual claim as to what a "normal" or "perfect focal length for a normal lens" is; my statements were meant to be conditional, i.e., "if you define X to be Y, then Z will be W." I apologize if I made you recall any previous "religious" forum wars and the associated anxiety.
05-11-2009, 04:06 AM   #66
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QuoteOriginally posted by soccerjoe5 Quote
I've always been stumped as to why a LOT of people here, and pretty much everywhere, always recommend newbies to buy all these expensive f/2.8 zooms and fast glass in their first few months. Here in my country and in our local photo communities I always see newbies asking "what should I buy next?" with no real clue as to why they need/want to buy. Then people surge in with answers "f/2.8 Nikkor/Canon L lenses" of all focal lengths.
I haven't seen that in a while (people advising blindly to buy f2.8 lens and whatnot)... most of those who reply in DPP usually ask what is the need/want of the threadstarter if he/she hasn't stated one yet. For example this thread:

Lens for my needs... - Digital Photographer Philippines

On the contrary, most folks over in DPP are advising to maximize the use of a newbie's kit lens first before venturing out to buy a new lens.

Of course, having a need is different from wanting something. If someone wants a fast zoom for example because the white external coating of a Canon L looks cool then IMO there's nothing wrong with that.
05-11-2009, 05:12 AM   #67
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I'll put it this way:

You are a mediocre photographer taking mediocre pictures with your mediocre kit lens.

You get a $800 uber lens to replace the kit lens.

The real world practical difference? -

Now you will be able to take sharper mediocre pictures.
05-11-2009, 05:45 AM   #68
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QuoteOriginally posted by wildman Quote
I'll put it this way:

You are a mediocre photographer taking mediocre pictures with your mediocre kit lens.

You get a $800 uber lens to replace the kit lens.

The real world practical difference? -

Now you will be able to take sharper mediocre pictures.

True, except for one thing - the nicer lens will give encouraging results, prompting the shooter to shoot more and work on technique in the process.

Note: "nicer" doesn't mean expensive, although it's hard to get cheaper than the kit lens. Consider The Tamron 17-50 2.8 zoom or F/FA 50 1.7 ($120 - $170) or even jumping ito MF primes to supplement the kit zoom.

Once you see the magic of a really nice lens, or any fast lens for that matter, you start to shoot more. I know people who's XT's and D40's sit in a drawer untouched because they were never given the advice of a kit lens upgrade, and they grew bored with the quality they were getting indoors.

I have to say that I'm on the other side of the issue here, Diego - If someone expresses an interest in getting better to me, I'm going to suggest a fast prime or constant-aperture zoom, and suggest they start honing technique from there - much more encouraging than just owning the slow kit zoom. I mean, the kit zoom can teach you something about framing and composition, but you can learn that from a 5x or 10x zoom point and shoot, also.


Last edited by jsherman999; 05-11-2009 at 05:52 AM.
05-11-2009, 06:45 AM   #69
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QuoteOriginally posted by rparmar Quote
Actually, the mystery is somewhere different.

Look through the viewfinder with the FA43 on the camera and then look out at the world. Your eye does not need to adjust at all. The size of shapes and the angles you see match up perfectly. That's what makes it the most natural focal length. You can frame shots with your eyes and then pull the camera up and shoot. Like you can on a rangefinder.

The mystery is that this is the same on film or the cropped sensor. The FA43 is a perfect fit for the eyes on both, even though it is not normal on APS-C. I mentioned this on another thread but no-one has been able to explain why it is so.
I think it may depend somewhat on the camera model, oddly enough. On the SV the exact same phenomenon may be observed with a 55mm lens. Hold it up in portrait orientation, open both eyes, and you'll think one eye is looking straight through a hole cut in the camera.

Since you mention rangefinders, many of the old fixed-lens rangefinders came with lens in "oddball" focal lengths of 45mm, 48mm, etc.

Our friend Wildman has an excellent point. Speaking just for myself, I am able to take wonderfully mediocre photos with any camera/lens I own. It is the one ability I have full confidence in.
05-11-2009, 08:12 AM   #70
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QuoteOriginally posted by mazdamazda Quote
I haven't seen that in a while (people advising blindly to buy f2.8 lens and whatnot)... most of those who reply in DPP usually ask what is the need/want of the threadstarter if he/she hasn't stated one yet. For example this thread:

Lens for my needs... - Digital Photographer Philippines

On the contrary, most folks over in DPP are advising to maximize the use of a newbie's kit lens first before venturing out to buy a new lens.
Good for you (for not seeing those kinds of threads) and for DPP then.

I haven't been spending a lot of time on DPP anymore, but it's not on DPP in particular. However, I've seen a good number of threads asking "what lens next" or "this lens vs that lens" that are apples vs oranges. How can one recommend one focal length over another, when I believe only the person asking can really answer that. To be particular, I see a lot of those posts in Pipho. Although, I've also seen a number of them in the Lens section here.
05-11-2009, 08:18 AM   #71
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Hey Marc, I actually know all about focal length, perspective etc. which is why my empirical observations were confusing me. Yes, I can feel my eye muscles adjust between the viewfinder and the "real world" if I use anything other than a 43mm lens on my K20D. This is not based on objective measures or any theory, just observation.

True, this is not to say the finished photo looks like what my eyes would see. I know about peripheral vision and how the eye constructs this, also about micro-saccades etc. though this seems to have little bearing. For me the most "natural" FOV in the finished photo comes about from a 28mm lens. I have compared quite rigorously with 24mm etc. This is a subjective view, but authenticates for me, all the guff about "normal".

QuoteOriginally posted by Marc Sabatella Quote
It's not really mysterious at all once you realize it is all about viewfinder magnification.
That partially makes sense. Although it might lead to the conclusion that for APS-C we need a 28mm lens with a viewfinder magnification that creates an impression of having a 43mm on the camera.

Otherwise this is finally a good argument for full-frame. Perhaps I am late coming to this realisation. Still learning here, and all.
05-11-2009, 08:43 AM   #72
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QuoteOriginally posted by jsherman999 Quote
True, except for one thing - the nicer lens will give encouraging results, prompting the shooter to shoot more and work on technique in the process.

Once you see the magic of a really nice lens, or any fast lens for that matter, you start to shoot more.
I would hope this to be true most of time. However, I've seen people be intimidated by an expensive lens - they are afraid to use it for fear of damaging it, or else their images do not immediately improve by a factor equal to the price they paid.

I think it's best to wait until you're in a situation of need before buying a 'better' lens. Of course, I don't follow this advice myself, LBA and all. But for someone with self control and a sensible budget, it's the logical choice.
05-11-2009, 10:47 AM   #73
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I think the magic of a top quality lens is not apparent to most beginning photographers. The Pentax kit lens will be so much better than anything taken with a non-slr, that I'm not sure how much more magic will be created for quite some time.

Also, FWIW, I found that the differences in lenses are far less apparent in the 10mp digital world, than in my former world of Kodachrome and B&W.
05-11-2009, 11:11 AM   #74
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Diego

I agree with you to a point.

everything you state is true, and a kit lens, or a 2 lens kit may be most that some people ever need. they cretainly are enough as you state, to learn the art and science of photography enough to know what you may want next. (this specifically applies to just getting 1 kit lens)

the real issue is that no one tells you how to plan oout your personal lens road map, or how to deal with what some call the obsessive compulsive behavior of LBA.

In my mind, for someone just starting out a kit lens is great value for the money. Probably the most value for money you will ever get in a lens.

But there are 2 types of people for which the Kit lens is useless (or nearly so)

-the first type is a person who is an experienced photographer who either knows what they want and are getting a new system, or who already has legacy glass and just does not need the kit lens (unless it fits a missing niche)
-the second kind is the person who, as others have stated have more money than brains, and buy a ton of high quality stuff, and then sell it when they can't get results that others have taken years to learn the technique for.

Personally I love the second type, because they create a source of used lenses for the rest of us
05-11-2009, 11:15 AM   #75
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QuoteOriginally posted by asdf Quote
Supposedly, indeed. I didn't write "perfect focal length." I wrote "``perfect''" (the quotes indicating ambiguity and arbitrariness) for a "normal" lens, a word that has a specific (however arbitrary) meaning in the given context.
Excellent! I figured you knew better, but I wasn't sure it was clear in the context of the discussion.

QuoteQuote:
I apologize if I made you recall any previous "religious" forum wars and the associated anxiety.
Luckily, I have a very short memory when it comes to that sort of thing :-)
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