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10-13-2021, 04:29 PM   #121
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QuoteOriginally posted by slartibartfast01 Quote
I suspect most people using phones don't know what focal length is.
Indeed!

And the same could be said of users of Fuji Instax, Polaroid SX-70s, GoPros, webcams, pocket 110s, Kodak instamatics, and so on all the way back to the first Brownie cameras.

The deeper issue is that focal length is not really meaningful in the context of casual photography for someone with a single, fixed lens camera. Sure, an optical engineer could use the numerical focal length and format size to predict key characteristics of images from these cameras such as angle-of-view and depth-of-field, but the average person does not really care. The viewfinder of the camera provides much better intuition about angle-of-view than any numerical formula.

It's only if someone has multiple lenses (or lens choices), that focal length becomes something worth knowing. And if someone has multiple cameras or cameras choices of different formats, then something like equivalence becomes worth knowing, too.

But in the mean time, the proverbial 99% of people who only have a phone camera or a compact P&S camera really don't need to know anything about focal length.

10-13-2021, 09:39 PM   #122
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QuoteOriginally posted by Alex645 Quote
If you look up the new Apple iPhone 13 Pro Max, under specs, they only define the three lenses as telephoto, wide, and ultra wide. They do state the f/stops and the optical zoom amount, but no reference to focal lengths.

I do use my smartphone to take photos, but I couldn't tell you what the focal length is nor the FF equivalence. I can guess and I can research it, but if asked, I'd just say it's "wide".
Yeah, Apple is often very vague on the specification. But not all manufacturers are. This is how Sony market the Xperia 5 III. The first minuter is about the camera and they are very specific about focal length.
10-14-2021, 06:57 AM   #123
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I just consider the FL as part of the nomenclature. We can't all be Kerrowdowns and name all our lenses. 100mm is a fine name for a lens, and it actually tells you something about the lens.There's never confusion about which lens you're talking about. But it's completely unnecessary with fixed lens cameras. With a fixed lens, you have what you have. Everything you need to know is seen through the viewfinder.

I use my 100 macro on FF or APS-c without consideration of sensor size. I like it better than my FA 50 macro or my Sigma 70 macro. So I just use it on both. FF and APS-c. And I can do pretty much the same thing with both. It's still 1:1 magnification. Whenever we get not this discussion, I always wonder, what is the practical worth of knowing the equivalence, when in so many circumstances I can just pick my lens based on other criteria, (for the D FA 100 macro, weight, size, WR and performance) and use it on any ILC including my Q. Equivalence makes int sound like using the Sigma 70 on APS-c is the same as using The 100 macro on the K-1. Nothing could be further than the truth. Because of the different characteristics of the lenses, Id rather use the D FA 100 on both. It's a very aware circumstance where I would have to know equivalence to get a shot. I've used this knowledge once.

I shot K-3 70 macro images to compare to 100 macro K-1 images, to show how little difference there is between the two formats. (At 3840x 2160 there essentially is none.) Apart from that, equivalence is one of those debating room topics with little practical use. Usually it comes down to "I need shorter" or "I need longer" and that could be determined without equivalence.

Equivalence is one of those topics that people debate endlessly, even though in the field, it's pretty much useless.

But I'm open to insight here.

How many of you have had an incident where you actually used equivalence in the field?
Not the usual "You could have this particular theoretical situation." BS.
I'd like to know if anyone has actually ever used it to help take a picture?

Were you ever in a situation where you thought I need wider than my DA 28-105 on my K-1 , I'll use the DA 16-85 on my K-3. You'd need to have both bodies and both lenses with you. How often does that happen? I use my camera bodies like that sometimes, but it comes down to "I need longer" or I need wider". If I have the Tamron 300 2.8 with the 1.4 on my K-3 and need wider, I may take the K-3 off and use the K-1. But I don't need equivalence per se. I need to know longer or wider. It's a very rudimentary form of equivalence, but nothing like the multiplication nonsense people seem to think we should go through.

I'd like to know if anyone has actually ever used it to help take a picture?
If not, it's an intellectual exercise, not essential photographic knowledge. It's not the equivalence isn't real. It's that it isn't necessary in the way it's presented. It's time wasting overkill that will hinder your photographic experience if you dwell on it. Do you have to accelerate to 100 mph and slam on the breaks and measure the skid to determine if your brakes are working? You don't need to measure the skid marks. That information isn't necessary. You don't need the equivalence formula either. Just a rough understanding of what it means.

Has anyone actually used the equivalence formula in the field? (Like stopped what you were doing to work out the math?)

Inquiring minds want to know.

My experience was, I used photographic knowledge to get it done before I even knew there was a thing called equivalence. (It wasn't part of the photographic curriculum at Ryerson.) And my photography didn't suffer even once. To me it's like a make work project. It's one legitimate use is describing the field of view of small format cameras, where it would not otherwise be obvious. Information you need to buy the camera , not use it.

Last edited by normhead; 10-14-2021 at 07:32 AM.
10-14-2021, 10:24 AM   #124
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QuoteOriginally posted by Fogel70 Quote
Yeah, Apple is often very vague on the specification. But not all manufacturers are. This is how Sony market the Xperia 5 III. The first minuter is about the camera and they are very specific about focal length.
https://youtu.be/NvdKscFh5zA
The video seems to be targeting consumers into photography...so the numbers become the bait. On the first hit when I google Sony Xperia III, the first page that lists features omits focal length: https://electronics.sony.com/mobile/smartphone/all/p/xqbc62-b

Eventually when you hit the specifications tab, you can find the focal lengths noted.

What I do find significant bringing this back to the OPs question is that the 16mm, 24mm, 70mm, and 105mm Zeiss T* optics on that Sony phone are just the 35mm equivalence and not the actual focal length of the lenses on the phone. I will give brownie points for anyone that can find the actual focal length of the lenses on the Sony Xperia III.

So that begs the next question: Should people (Sony) use the actual mm non-equivalence terminology?

10-14-2021, 03:23 PM   #125
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QuoteOriginally posted by Alex645 Quote
The video seems to be targeting consumers into photography...so the numbers become the bait. On the first hit when I google Sony Xperia III, the first page that lists features omits focal length: https://electronics.sony.com/mobile/smartphone/all/p/xqbc62-b

Eventually when you hit the specifications tab, you can find the focal lengths noted.
FF EQ focal length is one of the first specification mentioned about the cameras. Although that is a different cameran than I linked to.

QuoteQuote:
What I do find significant bringing this back to the OPs question is that the 16mm, 24mm, 70mm, and 105mm Zeiss T* optics on that Sony phone are just the 35mm equivalence and not the actual focal length of the lenses on the phone. I will give brownie points for anyone that can find the actual focal length of the lenses on the Sony Xperia III.
That the smartphone manufacturers state AOV in FF EQ focal length has become such a common standard that they no longer need to state that it is FF EQ focal length.

Just like when you see a speed limit sign in the US, it is not necessary that it state that it is in mph.

QuoteQuote:
So that begs the next question: Should people (Sony) use the actual mm non-equivalence terminology?
Using actual focal length on smartphones has little point as each camera on the smartphone may use different sensor size, so there is not necessary a clear relation between actual focal length and AOV on these cameras
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