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06-04-2009, 08:12 AM   #1
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idle curiosity: who decides prime focal lengths?

I have so much work to do this morning that I'm paralyzed and driven over here to waste time until I get the courage to go back to work. And this is something I've been curious about: What factors decide the focal lengths for prime lenses?

For example, there's a Pentax 21. Is there a 22 or 23? If not, why not? I have the Sigma 28, Pentax 35 f/2 and 50 f/1.4. Does anybody make a 29, or 37, or 52?

I can think of several things I might say if somebody (mistaking me for an expert on lenses) were to ask me that question. But I bet somebody here can give a better answer than I would make up for myself.

Will

06-04-2009, 08:29 AM   #2
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Most manufacturers round up the number for the focal length. A50 mm. lens can actually be 52 or 47. So, beside Pentax Ltd lenses, you never know the real focal length of your lenses.
06-04-2009, 08:45 AM   #3
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Interesting thoughts.

I've also wondered about FL choices. Why is there no 17 or 18mm equivalent to the compact 15mm? Why is there no fast DA 35mm "normal", which gives the equivalent of a FF 50mm FOV? I'm sure Pentax engineers and other more wizened souls could explain it, but I have been somewhat surprised that there are not more DA primes that closely approximate the FOVs and speeds to which many of us who spent decades in the 35mm film world have become accustomed.
06-04-2009, 09:38 AM   #4
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QuoteOriginally posted by GeneV Quote
Interesting thoughts.

I've also wondered about FL choices. Why is there no 17 or 18mm equivalent to the compact 15mm? Why is there no fast DA 35mm "normal", which gives the equivalent of a FF 50mm FOV? I'm sure Pentax engineers and other more wizened souls could explain it, but I have been somewhat surprised that there are not more DA primes that closely approximate the FOVs and speeds to which many of us who spent decades in the 35mm film world have become accustomed.

Oh Gene, they are not making cameras for us old photog fogies anymore.... Look at the KM or even the new K7 video camera... these are designed and marketed to the masses... The soccer families of the world. That is where the money is.

And prime lenses are an afterthought for that market. How many $700 DA 55's or $ 550 dollar DA 35's do you think 'Joe and Joanne in the mini-van' are buying? The answer is none!

It makes more sense financially for Hoya to design the WR kit package that will sell, rather than spending time designing the most obvious holes in the "old fogey" wish list

Give me a fast WR 28 F2 and/or 35 1.4 with creamy OOF areas...

Or at least a WR DA 28-75 2.8 for the Joe and Joanne's of the world.

06-04-2009, 09:53 AM   #5
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True enough. For the masses, why make primes at all? The kicker is that primes get pros and serious amateurs to use the product, which in turn sells "the masses" on the idea they are using something cool.

I'd love to see a sharp DA Ltd 35mm 1.4 (such as barely existed for Pentax film cameras), or I'd settle for a 1.8 or 2. The various old 35/2s were/are a nice lenses, but they could use some updating to the digital world.
06-04-2009, 10:07 AM   #6
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I was actually blown away that Nikon released that $200 35mm 1.8 prime this year... Maybe that will be a signal to Pentax and the others that it is time to make reasonably inexpensive, fast primes for Joe and Joanne. And for us too!

Last edited by Igilligan; 06-04-2009 at 10:13 AM.
06-04-2009, 10:46 AM   #7
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QuoteOriginally posted by Igilligan Quote
I was actually blown away that Nikon released that $200 35mm 1.8 prime this year... Maybe that will be a signal to Pentax and the others that it is time to make reasonably inexpensive, fast primes for Joe and Joanne. And for us too!
Any word on whether it is any good?

Don't tell Pentax, but I'd pay more than that if they decided to follow suit.
06-04-2009, 06:30 PM   #8
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its a fact amongst leica photographers that Leica and Zeiss fast 50's are all 51.6mm lenses..and some of pentax's higher range 50s from the 80's mimicked this.

06-04-2009, 06:31 PM   #9
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I guess my opinion is a little different. I think a lot of people are atracted to photography the moment they have kids. Joe and Joanne want to remember the good (and bad...) moments with their kids. You are right when you say that's were the big bucks are. However, I also believe, based on my personal experience, that some of the Joe and Joanne outthere will eventually want to push photography a little further. They will get to the point where they realize the limitations of the kit lens. Then, they will do a little bit of research, find this forum and decide to buy one more lens. They discover they can do more than just take pictures of their kids and that's when LBA starts. Thus, I guess Pentax needs to bring newcomers to them with reasonable and afordable products and retain them by offering top of the line primes and zooms. The problem is, considering their limited resources, this means the must take some tough decisions to keep this fine balance.
06-04-2009, 07:01 PM   #10
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QuoteOriginally posted by SylBer Quote
I guess my opinion is a little different. I think a lot of people are atracted to photography the moment they have kids. Joe and Joanne want to remember the good (and bad...) moments with their kids. You are right when you say that's were the big bucks are. However, I also believe, based on my personal experience, that some of the Joe and Joanne outthere will eventually want to push photography a little further. They will get to the point where they realize the limitations of the kit lens. Then, they will do a little bit of research, find this forum and decide to buy one more lens. They discover they can do more than just take pictures of their kids and that's when LBA starts. Thus, I guess Pentax needs to bring newcomers to them with reasonable and afordable products and retain them by offering top of the line primes and zooms. The problem is, considering their limited resources, this means the must take some tough decisions to keep this fine balance.
That is certainly true for some, but in reflecting on this thread, I am not sure how Joe and Joanne really fit into the digital SLR market. I was at a wedding last weekend with lots of Joes and Joannes. Almost everyone there had a camera. The only SLRs were mine and the pro who was paid to shoot the wedding.
06-04-2009, 07:42 PM   #11
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QuoteOriginally posted by GeneV Quote
Any word on whether it is any good?

Don't tell Pentax, but I'd pay more than that if they decided to follow suit.
From what I've seen it's quite decent. I wouldn't pit it against the 35 macro or the 31 ltd but for $200 (and an internal focus motor, thus including their lower-end D-SLR owners) it's a great deal.
06-04-2009, 08:29 PM   #12
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Ummm...who are Joe and Joanne?

c[_]

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