rehess Loc: South Bend, Indiana, USA

Do a simple web search
https://en.wikipedia.org/wiki/American_National_Standards_Institute
and you will discover that the organization which is currently called ANSI went through several names over the years, one of which was ASA.
Film and cameras commonly used the ASA (plus DIN) nomenclature until ISO adopted the American standard.
My old Pentax Super Program (1984) must date to the years when they were transitioning from ASA to ISO.

Pentax Super Program dial to set film speed

Peterff Loc: O'er The Hills and Far Away, in Themyscira.

I had my tongue in my cheek when I posted that question, I'm quite familiar with the American Standards Association and Deutsches Institut für Normung. Thanks for posting the link anyway, it may help others with an interest to know.

My AE-1 (1976) has ASA ratings, my T90 (1986) has ISO numbers, my Brownie 127 (~1962) doesn't have any at all!

Cheers

Rufus Loc: Puget Sound area, WA

To me, at this time, the most important specification for a lens is "angle of view" for either a FF sensor or a more narrow sensor. It is easy to calculate this but a nuisance. Example: I recently wanted to know if changing from 28-70 focal length lens to a 24-70 lens would give me the increased angle of view I needed. (The answer was yes.)
Rufus

SharpShooter Loc: NorCal

ISO....??, ISO....??, I don't need NO STEENKEEN ISO!!!
I just put my crappy little camera on the BIG FAT green "A" and shoot away!!!
I don't worry my pretty little head with things like ISO..., DIN...., or ASA.
It makes my pretty little head HURT!!! :lol: :lol: :lol:
SS

frankie c Loc: Lake Havasu CIty, AZ

lol.. My original reply was tongue in cheek. Then I watched as this conversation took on a life of it's own. I couldn't resist playing along. So many opinions and so many issues. Time for me to un-watch. Thanks for the fun.

Blasthoff Loc: Life halved NY and IN

Sounds like a plan! I've got an old camera, it doesn't have an A. I'll try plan B! LOL

:mrgreen:

rehess Loc: South Bend, Indiana, USA

Yes, something like that would be very useful, but I'm not quite sure how it would be implemented.

For example, I currently use two cameras, a Pentax Q-7 (crop-factor=4.7) with a 5-15mm lens amongst others, and a Pentax K-30 (crop-factor=1.5) with a 18-55mm lens amongst others.

I find myself asking questions such as:

* if I need to grab a camera and take a very wide shot, which lens will give me the widest view?
{answer: 5mm on the Q-7, which is equivalent to 23.5mm on FF, is wider than 18mm on the K-30, which is equivalent to 27.0mm on FF}

* if I mount an old 28mm Pentax-M lens on the K-30, how does the view compare to what the 50mm lens gave me on the 35mm film camera?
{answer: 28mm on the K-30 is equivalent to 42mm on the film camera}

I currently have a spreadsheet that I use to keep track of what my various lenses do on the two cameras, but it should would be nice to have a portable solution {yes, I can access the spreadsheet from my phone, but that is not quite what I have in mind}


This is not for the amusement or dismay of others.

We have entered upon a serious area where some of us deal with serious questions on a regular basis; this whole business of "equivalent focal length" causes serious confusion, and as I have indicated above, some of us have to think about these things on a regular basis. I value my time as a user of 35mm film - it provides a solid basis for everything I do today - but this area is one in which I don't really have tools for serious thinking today, and I don't yet see the beginning of tools of the future that will help our grandchildren (who will never see a film camera away from a museum or the back corner of Grandpa's closet) to deal with them either.

sonic Loc: chesterfield UK

I believe that we should stop referring to focal length
as seen from a 35mm point of view .
With all the different size sensors it does make things a bit confusing .
Or if we do continue then if a lens is made for a a certain censor then at least state the equivalent focal length .
If a 50mm lens is designated DX , It should be 75mm .
How hard would it be to put on the side of a FF lens ,FF 50mm ,DX 75mm .
sorry if this makes no sense to you .

rehess Loc: South Bend, Indiana, USA

Oh, it makes sense to me, but what if I use a DX/EF-S lens with an adapter on my Pentax Q-7 (crop-factor=4.7), or on an m43 camera (crop-factor=2), or ... ?

SwedeUSA2

I don't think your little head is pretty after reading your post, but little... sure! And hurting, absolutely!

SwedeUSA2

This is exactly why we need a common reference point not to make it confusing. It makes it understandable to all except those who don't understand. :mrgreen:

GoofyNewfie Loc: Kansas City

As I said today in another endless thread on the subject:

Because.
It's.
A.
50mm.
Lens.

The focal length of a lens is measured the same way on all lenses- regardless of the sensor intended.
If you screw with the real focal length what happens to the aperture value which is tied to the focal length?
It's a ratio of the focal length to the diameter of the lens opening. New can of worms there.

If you really feel the need to know the "full-frame equivalent", learn the factor for your camera (easier if you're shooting MFT- double whatever you're using) or just look through the finder and work with what you see. Some people are overthinking this.

Blasthoff Loc: Life halved NY and IN

Well, if someone is new to a format they probably would need to know this stuff in order to buy the lenses for the coverage they need. Otherwise, if lenses were at ones disposal, I'd completely agree with you.

Bram boy Loc: Vancouver Island B.C. Canada

I could write it in Norsk , but you may have a tougher time reading that , or French . do you talk English or that swamp water garble that is know as southern accent in some states .

Bram boy Loc: Vancouver Island B.C. Canada

And who do you think taught you English . The only american lingo was apache , Mohawk , sue, and a couple others . All spoke the true language of
USA and Canada . How many words of that can you speak . Don't call the
Kettle black until you know your own true colors