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01-30-2019, 02:58 AM   #436
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QuoteOriginally posted by Kunzite Quote
I believe you were - and still are - completely honest; you indeed are relating things as you see them.
Thanks, Alex. I appreciate that

QuoteOriginally posted by Kunzite Quote
What I said stands. It's your choice how you do your photography projects, however IMO it's the subject, the composition and one's intent that leads to a choice of focal length and aperture. You started with the settings instead of determining them from what you want to get.
We agree!!!

I made a choice on how to approach something, and my approach is different to yours - but both of us would have been able to achieve my original goal. You believe, as you're absolutely entitled to, that your approach is preferable and less confusing. I can't comment on that with any authority, and in any case, my comment would be coloured by my own preferences.

For what it's worth... although I've used equivalence to my benefit, I still make my own independent lens choices in relation to shooting conditions. If I'm going to a car show, I don't look online to see what lenses other folks have used, then apply equivalence to choose something from my own kit bag. I just know I'm going to need a wide angle lens. In fact, given the number of people there and the likelihood that I won't be able to get much distance between myself and each car, I'll probably need a very wide angle lens, or perhaps a zoom that covers very wide to wide. And if I'm asked to take a head and shoulders portrait of a family member in their home, I know I'll want a short tele - something that will allow me to work within the constraints of the room, yet still be flattering to their facial features.


Last edited by BigMackCam; 01-30-2019 at 03:08 AM.
01-30-2019, 03:31 AM - 1 Like   #437
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QuoteOriginally posted by photoptimist Quote
Different strokes for different folks.

Personally, when I look at Bill's shots, I can't tell exactly how far away the subject is from the camera or how far away the background is at a glance. Sure, it's obvious that it's wide, but how wide? Accurate subject and background distances are seldom in the EXIF data. I could use photogrammetry to figure it all out but that's a lot of work!

But the sensor size, focal length, and aperture often readily available for the photo. With just 15 seconds on a pocket calculator (requiring entry of a total of four numbers, one division, and two multiplies) tells me what focal length and aperture I should try to jumpstart my use of his style.

To me, this about quickly estimating what size horse I need on the front of my particular carriage.
Exactly

And with respect to the highlighted portion above, I dare say you - most of us, in fact - don't even need to pull out the pocket calculator if the crop factor we're dealing with is something simple like 1.5x or 2x. We can get the answer in our head in seconds.

QuoteOriginally posted by swanlefitte Quote
If 35mm film and I know the fl it's easy to convrrt to apsc since I know it's 1.5x.
Funny enough I could tell Bill used a 35mm.
Yes, you can convert from 35mm film to APS-C using that 1.5x crop factor... The focal length part of what we've discussed as equivalence.

Since you could tell Bill was using a 35mm lens, you wouldn't have benefited from the approach I used had you set out on the same project. You'd have just picked up a 35mm lens for full frame, or 24mm on APS-C, and got on with it. I could tell he was using a moderately wide angle lens, but wouldn't have been so confident as you in determining the focal length...

Last edited by BigMackCam; 01-30-2019 at 03:55 AM.
01-30-2019, 06:34 AM - 2 Likes   #438
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QuoteOriginally posted by photoptimist Quote
Personally, when I look at Bill's shots, I can't tell exactly how far away the subject is from the camera or how far away the background is at a glance. Sure, it's obvious that it's wide, but how wide?
The crazy thing is Bill himself probably picked his focal length by trial and error, and just stuck with what worked. He spent a fraction of the time making this decision that has been wasted defending equivalence on the forum. There's something to be said for originality.

Last edited by normhead; 01-30-2019 at 07:17 AM.
01-30-2019, 07:30 AM   #439
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QuoteOriginally posted by Fogel70 Quote
I do not see any reason why this would change if primes did not exist.
Zooms changed my entire style.

With primes I picked the lens, then found a place where framing worked.
With zooms, I pick the perspective I want then zoom to get framing I want; seldom do I even notice what focal length I ended up with.

"Equivalence" works much better with the former approach than with the latter.
Incidentally, I was using zooms when I moved to digital, which may be why "equivalence" is relatively meaningless to me.

01-30-2019, 07:52 AM   #440
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QuoteOriginally posted by reh321 Quote
Zooms changed my entire style.

With primes I picked the lens, then found a place where framing worked.
With zooms, I pick the perspective I want then zoom to get framing I want; seldom do I even notice what focal length I ended up with.

"Equivalence" works much better with the former approach than with the latter.
Incidentally, I was using zooms when I moved to digital, which may be why "equivalence" is relatively meaningless to me.
Exactly. My basic zoom set up is two lenses, the 18-135 and either the 60-250 or 55-300 PLM. I have actually done tests, using the same lens on a K-5 and k-1, adjusting the focal length so I had the same framing for both images. I didn't need any theory at all, I just pick a few features I want to define the edges of the frame and frame as desired. Zooms make equivalence completely obsolete. And because my prime images are so often cropped, you have to be really lucky to find the exact framing you want with a prime, I generally get more resolution etc. with the zoom, because I crop to the framing I want, using the whole frame for the image. You could carry 20, 24, 31, 35, 40 50, 70 and 85 primes instead of a 16-85 and you'd still have times when you needed 45 mm, or 60mm, and waste sensor real estate going to the next lens down. I find with a good zoom, I rarely even come up with a number in my exif that corresponds to a prime, and almost never to a prime I actually have in my bag.

The big advantage to zooms is not that they can compete with primes, although my DA*60-250 certainly can. It's that in primes I have 50mm, 55mm and 70 mm. 3 focal lengths. With the 16-85 you have all the numbers in-between. If I can shoot the 16-85 at 80mm, when I would have had to go to 70mm using primes, I've saved myself 10% of the resolution by using a tighter frame. People buy new lenses for a 10% increase in resolution.

Just saying.

Last edited by normhead; 01-30-2019 at 08:05 AM.
01-30-2019, 08:54 AM - 1 Like   #441
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QuoteOriginally posted by swanlefitte Quote
If primes don't exist are we having this conversation?
It's not the fault of primes. Even with zooms there's the open question of relating the focal lengths to the FoV, AoV, or perspective effects provided by that lens.

The real reason for this issue is interchangeable lenses, especially the ability to put a given lens in front of sensors or film of different formats. If all cameras only came with built-in lenses, then the most sensible way to describe the lens would be the relative or normalized focal length -- focal length measured in sensor or format widths. Thus, portrait cameras would come with a 2x-format-length lens, UWA cameras would come with a 0.6 or lower lens, and the BIF folk would brag about cameras that come with 10x or 15x-format-length lens. Nobody would have to muck with crop factors or equivalent focal lengths.

What makes all this confusing is that the focal length measured in millimeters only tells us something technical about the optical properties of the lens. Focal length does not tell us anything useful about the photographic properties of the lens such as is the lens wide, normal, or telephoto. Those photographic properties only emerge when the lens is mounted in front of a sensor or piece of film. A 100mm lens is a UWA if put on a 4x5, a normal if put on a 6x7, a telephoto on APS-C, etc.

What sucks about "equivalent focal length" besides enshrining a one special format that only some photographers use is that it seems like a property of the lens when it is not. It's a property of the lens-camera system. Put a K-1 in crop mode and all the equivalent focal lengths of its lenses change. And yet for all the suckage of "equivalent focal length," it is widely used, beginners are confronted with it, and beginners do face the challenge of relating what is said about different lenses in different formats to what they can do with their own lenses on their own format.
01-30-2019, 09:46 AM   #442
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QuoteOriginally posted by normhead Quote
The crazy thing is Bill himself probably picked his focal length by trial and error, and just stuck with what worked. He spent a fraction of the time making this decision that has been wasted defending equivalence on the forum. There's something to be said for originality.
Trial and error can be a very time-consuming process because you have to give each lens a fair trial. You can't just abandon a lens because the first shots weren't great. Those monthly "single-in-" lens challenges suggest it can take month to really learn a lens. And a fair trial involving something like street photography requires a lot of indecisive wandering about to find those decisive moments. So, doing Goldilocks and the three lenses (20, 24, 28) for street really could take months.

So if someone like Bill has done the laborious trial and error part of lens selection for a style of photography, Mike or I might like to reuse that hard-fought knowledge to jumpstart our own creations.


P.S. I personally find wide and ultrawide angle lenses much hard to master than normal and telephoto. Composition is a lot easier with longer lenses because small changes in camera location let one quickly adjust the background, frame the subject, isolate the subject, etc. UWA takes in so much of the foreground (including the photographer's feet) and background that it takes much more physical movement to properly manage the composition (thank you K-1 tilty screen). Also, UWA is a lot more sensitive to at-an-angle subject-camera positions that create crazy keystoning of rectangular objects.

01-30-2019, 09:46 AM - 1 Like   #443
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QuoteOriginally posted by Kunzite Quote
Thank you for saying it out loud - "equivalence" is pseudo-science (I would say religion, but some people might not be happy about that)

OTOH wasn't I offering simpler, clearer and more direct approaches all this thread?
For example, if you want to recreate an image's close up perspective, I would advise someone to move closer. What could be simpler than that?
Totally true. It's always puzzling to see people going to hell and back trying to calculate "equivalence" when all they really need is learning some basic century old photography knowledge. IMHO, equivalence is just a poor subsitute to ignorance...

As you said in previous posts, all one really need to know is what is the normal FL for the system they use (diagonal of the light sensitive surface). Sure, people have to know what is the size of the sensore they use. But if they're willing to calculate all kind of equivalence, I guess they should be able to learn something as basic as the size of the sensor in their camera.

From there, WA is anything shorter than the long end (and UWA anything shorter than the short length) and telephoto is anything longer than twice the long end. It works with any sensor (or film) size, no matter is 4:3, 3:2 or any funky size factor you may think of. It's just geometry, really... No need for a supposed "standard" format or calculation.

For DoF, the basic rules stays the same no matter the format. In you want more, close the diaphragm (small f number). If you want less to blur the background, open it (large f number). If it's not enough, use another lens with a larger aperture or longer FL, try to get closer to your subject, or find an angle to increase the distance between it and background. Much more useful and universal knowledge for a beginner than to tell you should buy an 35mm 1.4 equivalent lens for your system, which doesn't exist or force you to take a mortgage to buy.

And for people wanting to analyze the work to gain some knowledge to apply to their own, it's way more useful to make the relation to these basic universal concepts than blindly calculte equivalence. For example, you look at a portrait taken with a FF and a 85m lens and want to get some similar results. It's much more useful to understand that the guy used a short telephoto (because 85mm is not much longer than 35mm x 2 = 70mm definition of what is telephoto lens) and relate this to your own gear instead of thinking "I can't do that because there isn't any 56.67mm lens for my APS-C system". And to determine the aperture, just look at the picture. If the background is quite blurry and the guy used 1.8 aperture with it's 85mm 1.8, you shouldn't think "I should use 1.4 with my system" as the equivalence, you should rather think " the guy used the widest aperture to get thinnest DoF available with what he had on hand" based on principles. No need to learn or calculate equivalence. Just applying the priciples will get you the nearest you can with the gear you have. Meaning the end result could be quite similar if you use a FF, close enough with an APS-C, better if you use medium or large format, and somewhat good but as a blurry with a smaller format. But in this last case, you will at least know that you will have achieve the best you can do with the gear you have...

It's not really more difficult to take the time to learn these few universal principles than to learn equivalence which is only really applicable to some specific situations.
01-30-2019, 10:10 AM - 2 Likes   #444
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QuoteOriginally posted by photoptimist Quote
Trial and error can be a very time-consuming process because you have to give each lens a fair trial. You can't just abandon a lens because the first shots weren't great. Those monthly "single-in-" lens challenges suggest it can take month to really learn a lens. And a fair trial involving something like street photography requires a lot of indecisive wandering about to find those decisive moments. So, doing Goldilocks and the three lenses (20, 24, 28) for street really could take months.
If it takes months to learn the idiosyncrasies of individual {but related} lenses, all on the same camera, how can you learn much by importing knowledge from a completely unrelated lens on a completely unrelated camera {which will add its own idiosyncrasies to the problem}???
01-30-2019, 10:49 AM   #445
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QuoteOriginally posted by photoptimist Quote
Trial and error can be a very time-consuming process because you have to give each lens a fair trial.
Trial and error is a derogatory term used by "equivalence" advocates to name targeted practice.
The dangerous idea - "equivalence" advocates loves to harm unsuspecting beginners - is that targeted practice is somehow bad or unnecessary, that you can replace it with a "simple" formula. Well, no craft is learned without practice.

Instead of such targeted practice, it's "equivalence" that's more random - because people are encouraged to use focal length/aperture combinations with wildly different subjects and situations.

---------- Post added 30-01-19 at 07:53 PM ----------

QuoteOriginally posted by reh321 Quote
If it takes months to learn the idiosyncrasies of individual {but related} lenses, all on the same camera, how can you learn much by importing knowledge from a completely unrelated lens on a completely unrelated camera {which will add its own idiosyncrasies to the problem}???
Great point, one I tried to make several times in this thread.
But they don't care, they have a theory to spread.
01-30-2019, 11:07 AM - 1 Like   #446
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QuoteOriginally posted by Kunzite Quote
"equivalence" advocates loves to harm unsuspecting beginners
QuoteOriginally posted by Kunzite Quote
But they don't care, they have a theory to spread.
Alex, this is unnecessary and inflammatory. No-one in this thread loves to harm unsuspecting beginners. And no-one here is trying to spread equivalence as a theory. We're here to discuss and debate this respectfully, that's all.

There's a big difference between disagreeing with folks, and accusing them of nefarious intentions. Let's avoid the latter of these.

Thanks
01-30-2019, 11:20 AM   #447
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Mike, I'll remind you again how my arguments are constantly ignored, while continuing with rebutted pro-"equivalence" arguments (like that about its alternative being trial and error, or how it's somehow learning you all about a system you never use).
Nobody here wants to harm the unsuspecting beginners, specifically. But some are pushing this "equivalence", with the same effect. How would they take responsibility for it?
01-30-2019, 11:29 AM - 1 Like   #448
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QuoteOriginally posted by Kunzite Quote
Mike, I'll remind you again how my arguments are constantly ignored, while continuing with rebutted pro-"equivalence" arguments (like that about its alternative being trial and error, or how it's somehow learning you all about a system you never use).
Nobody here wants to harm the unsuspecting beginners, specifically. But some are pushing this "equivalence", with the same effect. How would they take responsibility for it?
I don't see any evidence of your comments being ignored - only that some folks agree with you, and some disagree. Nor do I see any evidence that anyone is "pushing" equivalence - only that some folks believe the concept has value. None of them is carrying a banner telling people "this is what you should do". Indeed, from what I've seen here, most of those who believe equivalence can have value admitted that there is some danger of confusion.

Anyway, let's move on and keep things respectful. This has been a great discussion, with valuable input from a range of members including yourself. I'd hate to see it degenerate into personal jibes and mud-slinging, as so many threads on emotive subjects tend to...
01-30-2019, 11:40 AM   #449
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Mike, I'm not angry at anyone - but this is, as I expected before you even opened the thread, turning into an exasperating discussion. It could've been about how mirrorless MUST replace DSLRs.

I wouldn't say my points are ignored if they weren't. People can miss things on a 30 pages topic but still...
For example, the thing with "trial and error", repeated several times. It is an idea convenient to the "equivalence" supporters. It was refuted, repeatedly, as being way off the mark.
And the point about "equivalence" being confusing... it's as if it never was made.
Instead, we're supposed to discuss contrived examples of beginners somehow knowing what a portrait lens works on a system they never touched.
01-30-2019, 11:43 AM - 2 Likes   #450
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QuoteOriginally posted by BigMackCam Quote
There's a big difference between disagreeing with folks, and accusing them of nefarious intentions. Let's avoid the latter of these.
Why does the word nefarious always remind me of Rocky and Bullwinkle?

But I have to agree with the basic information.... "trial and error" is being used as if it's somehow less valuable.
Scientific formulations are not even considered science until they are backed up with empirical data.

In other words theory (in this case equivalence" can only be substantiated through "trial and error". It might give bit of direction to your trial targets, but even that may prove unreliable in that you could be happy with a 40 on APS-c and unhappy with the only 60 you can find on FF. Equivalence does not reduce the need for trial and error, and it could save you time in that you know where to look, but it could cost you time in that what you find in that focal length doesn't create the look you want.

Anyone claiming you can do the theory without the empirical is selling you bill of goods.
After all the theoretcal constructs like equivalence you still have to go out and prove it with trials.
Given the difference in lens designs etc. it's pretty unlikely the suggestions provided by equivalence will lead to the best solutions to the problem.
After all, my FA 50 macro and the DFA* 50 1.4 produce very different results with the FA 50 macro being sharper edge to edge and the DFA 50 1.4 providing much smoother out of focus areas.

The FL is minor compared to the lens design.

Regardless of intent, one should not be intimating that equivalence will save time (that's not been proven), gives one a better understanding of different formats, that's also unsubstantiated, and it's limitations should be explained. It's not just equivalence at fault here. The only way to promote any shortcut, is to immediately point out it's limitations, especially for something like equivalence where all the claims made for it are debatable.

Most lens selections are made not using equivalence but by selecting something you might like from the categories. Ultra Wide angle, wide angle, standard, telephoto, aspherical, rectilinear, internal external focus, widest aperture and most important, what lens do you have now and why is it insufficient. Equivalence covers a little bit of that, but is in no way comprehensive, leaving us to debate over whether it actually saves any time or actually costs beginners time.

I personally wouldn't take anyone seriously one way or the other without some kind of hard evidence that what they say is true. Not even myself. Everything we have here about equivalence is that some people think it's a good thing, some people think it's misleading, and there's no actual evidence to say it's better or worse than any other method of picking out your next lens. In fact the only suggested use for it is is for the famous "beginner" shooting 2 formats (Is that even a thing.). Look at the criteria above and decide how useful it could possibly be. It just seems pretty insignificant to me. If others feel it's really important, that just means they approach things from a different mindset.
As long as you cover all the steps you need to in lens selection, spending the first 10 seconds of what should be hours of work determining which lens has the characteristics you want, the equivalence of the lens you want in a different format is probably neither here nor there.

Last edited by normhead; 01-30-2019 at 11:53 AM.
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