[jatrax]

You know, I keep thinking I should look at Sony's or Fuji's catalog for this comparison, but then it occurs to me that those are new mounts, rather than "old" reflex mounts like the K. One thing everyone seems to agree upon is that the flange-back distance makes a HUGE difference in lens size, so those wind up being immediately irrelevant.

I have no great experience with other brands but a quick look at Sony, Canon and Nikon for a 70-200 f/4 shows that Sony weighs 840gm, Nikon 850gm and Canon 771gm. Fuji does not seem to have a 70-200 but they have a 55-200 that weighs 580gm but is slower and variable aperture rather than fixed. Maybe I am looking at this wrong but I think you are making assumptions based on hearsay not facts.

Maybe someone else more familiar with these systems can point out other examples but I do not see that it is automatic that mirrorless lens are smaller or lighter. Maybe you could point out where it is stated that the "flange distance makes a HUGE difference in lens size" as that does not seem to be true as far as I can tell.

[atomx]

I have no great experience with other brands but a quick look at Sony, Canon and Nikon for a 70-200 f/4 shows that Sony weighs 840gm, Nikon 850gm and Canon 771gm. Fuji does not seem to have a 70-200 but they have a 55-200 that weighs 580gm but is slower and variable aperture rather than fixed. Maybe I am looking at this wrong but I think you are making assumptions based on hearsay not facts.

Fuji have a 50-140 f2.8 which is there equivalent of the 70-210 f4 in 35mm terms. It weights just on 1000g.

One factor that will increase weight of lens is the amount of optical correction the designers want to included in the lens to reduce aberrations, distortion...etc. These corrections increase the number of elements leading to increase weight and cost.

[Rondec]

Size of lens is obviously controlled by a mixture of things -- registration distance, mount size, focal length and aperture. Sensor size covered does have some bearing, but not a huge amount compared to the other things. For Pentax, the smallest lens is the DA 40, because that focal length is very close to the registration distance. For telephotos, there is some decrease in size to just cover APS-C versus full frame, but it isn't great considering that the lens mount is exactly the same.

Atomx is right that there is a tendency lately not to fix aberrations in lenses and just fix them with software after the fact. Sony has done a lot with this approach, but I must confess I am not a big fan. However a well corrected lens will tend to be larger and have more elements than one that isn't.

[fredralphfred]

Size of lens is obviously controlled by a mixture of things -- registration distance, mount size, focal length and aperture. Sensor size covered does have some bearing, but not a huge amount compared to the other things. For Pentax, the smallest lens is the DA 40, because that focal length is very close to the registration distance.

OK. There. That seems reasonable to me, even though I "learned" it over the Internet. (Just like everything else I'm hearing on this issue -- I don't have the time or cash right now to study engineering physics at a college.) And it explains some things, so I tend to believe it. That explains why 50's are relatively compact and cheap (vs performance) on 135 SLR mounts -- the focal length is close to the registration distance. I'm guessing that it has less of an effect the longer you get away from the flange-back distance, which explains why telephotos (seem to) enjoy less benefit than wide-angle lenses -- by their nature, they're going to be a greater multiple away in terms of focal length. It seems reasonable to me that the lens size would be more affected by the image circle size as other factors, like the flange-back vs. focal length, approach unity. Of course, I don't "know" this happens; I'm simply saying I've seen other things work that way, so it seems reasonable to me that that's how a camera lens would behave.

For telephotos, there is some decrease in size to just cover APS-C versus full frame, but it isn't great considering that the lens mount is exactly the same.

Atomx is right that there is a tendency lately not to fix aberrations in lenses and just fix them with software after the fact. Sony has done a lot with this approach, but I must confess I am not a big fan. However a well corrected lens will tend to be larger and have more elements than one that isn't.

That's another point I hadn't considered, although I would guess that would affect cost much more than weight or size. I would think those would be small, expensive elements at the back of the lens (although I don't really know -- perhaps there's some reason you need to put the corrective elements at the front).


Either way, it certainly points to a difference in philosophy in lens design that is likely system-wide for each manufacturer. I prefer the approach I've seen from Pentax -- make 'em as small as practicable, but make the lens do the work to get a usable image. I'm willing to sacrifice a little bit of speed for size, at least at the short end. But I don't want to post-process every photo just to make them look OK. (And I shoot raw, "just in case," so in-camera processing doesn't benefit me.)


I guess I should say that I'm now satisfied that the 150-450 wouldn't be significantly smaller/lighter/faster/cheaper if designed for APS-C because of its size vs. the mount, and I should shut up in case Ricoh decides it would be more "market friendly" to start making huge lenses every 2 mm that are really fast but require an assistant to lug around. I enjoy fast, but with the DOF I've seen on telephoto lenses and the direction ISO is going, I think they've been choosing a good mix there.


Thanks to everyone for a good discussion!

[Nicolas06]

Fuji have a 50-140 f2.8 which is there equivalent of the 70-210 f4 in 35mm terms. It weights just on 1000g.

One factor that will increase weight of lens is the amount of optical correction the designers want to included in the lens to reduce aberrations, distortion...etc. These corrections increase the number of elements leading to increase weight and cost.

Pentax has a 50-135 f/2.8 equivalent to 70-200 f/4 and it weight 685g... It work with a DSLR.

The tradeoff is simple: if you reduce the registration distance you may help to design of wide angle and ultra wide angle lenses but on the opposite it make teles bigger/heavier.

You can sumarize it this way:
Mirorless: small fast wide angle + smaller body (with less grip) and bigger teles. Special: support any lens in MF.
DSLR: possibly small (eg DA15, DA21, but not fast) wide angles, bigger body (with more grip) and smaller tele (think DA70, FA77, DFA100 macro, F/FA 135...). Special: OVF, high end model with advanced pro features.

Currently DSLR tend to have very great prices because they have been there for longer and there more interresting bargain to get.

[atomx]

The other reason why many of the pentax lenses are smaller is the use of screw mount ( FA limiteds, DA Limiteds...etc). Once you put DC motors into the lens it adds size too.

[Lowell Goudge]

Snip.........
One factor that will increase weight of lens is the amount of optical correction the designers want to included in the lens to reduce aberrations, distortion...etc. These corrections increase the number of elements leading to increase weight and cost.

Snip........

Atomx is right that there is a tendency lately not to fix aberrations in lenses and just fix them with software after the fact. Sony has done a lot with this approach, but I must confess I am not a big fan. However a well corrected lens will tend to be larger and have more elements than one that isn't.

I'm not so sure . For complex distortion so it may be better to deal "in lens" so to speak, but for some simple distortions, like lateral CA, in camera can do amazing things,

I have a sigma 28mm mini wide II which has really bad lateral CA, you should see what correct rescaling of the three colour layers can do for sharpness at the edges. I ran a thread on this a few years ago, to look at different CA correction techniques. If the ultimate design is simpler, and corrections are simple mathematical equations some times it is much easier to fix it in post, than dry and design an optical element to solve it in the analog world

[Rondec]

I'm not so sure . For complex distortion so it may be better to deal "in lens" so to speak, but for some simple distortions, like lateral CA, in camera can do amazing things,

I have a sigma 28mm mini wide II which has really bad lateral CA, you should see what correct rescaling of the three colour layers can do for sharpness at the edges. I ran a thread on this a few years ago, to look at different CA correction techniques. If the ultimate design is simpler, and corrections are simple mathematical equations some times it is much easier to fix it in post, than dry and design an optical element to solve it in the analog world

There just isn't a free lunch. Fixing distortion in particular will steal away some of the edges of your photo. A 16mm photo just won't be quite as wide after you fix it in post.

Vignetting is another area where companies are content to release lenses that are pretty poor. The Sony 35mm FE has 2.6 stops of vignetting without correction and even with in camera correction it has 1.6 stops. As long as you are shooting at low iso it probably isn't a big deal, but if you are at higher iso corrections probably are going to add noise to your image.

Probably the area where you just have to tolerate some weaknesses in glass is in zooms, particularly super zooms. But it seems like when you are getting a prime, they should engineer the lens enough that it doesn't need a lot of computer manipulation after the fact.

[fredralphfred]

. . . The Sony 35mm FE has 2.6 stops of vignetting without correction and even with in camera correction it has 1.6 stops. As long as you are shooting at low iso it probably isn't a big deal, but if you are at higher iso corrections probably are going to add noise to your image. . .

Odd. When you mentioned this, I immediately had the thought, "Well, they're Sony." Then, I thought, "Well, that's not right. Why would I let Sony get away with things I wouldn't expect from or would be upset with from Pentax?" And almost immediately, I answered myself, "Well, Pentax is a real camera company, and Sony isn't."


And unless they have very recently changed, I still think of Sony as a gadget company. I mean, I'm glad they're making cameras, because they're pushing the envelope, and hopefully the "real" camera companies. The a7 series is genius, and for a while the NEX really had something going for it in terms of demonstrating how much you can do with so little. But lens support is very sparse for both (at least compared to Nikon, Canon, or Pentax). While Sony has some sort of agreement with Zeiss, many times I wonder if it isn't just in name only. I think a majority of the Pentax lenses measure up to the Zeiss-branded Sony lenses. And the "real" Zeiss lenses for Sony are few and far between. There are some good Sony lenses out there, but Pentax seems to have a LOT of good lenses. The main reason I didn't buy Sony in the beginning, and wouldn't consider it now, is lack of native lens support.


I would let Sony get away with producing half a lens (meaning the "other half" is in software on a PC or in-camera processing) while I wouldn't let Pentax do the same thing. But I expect Pentax to act like a camera company.

. . . Probably the area where you just have to tolerate some weaknesses in glass is in zooms, particularly super zooms. But it seems like when you are getting a prime, they should engineer the lens enough that it doesn't need a log of computer manipulation after the fact.

And as I mentioned above, even with a super zoom, I would expect a Pentax super zoom to produce a reasonable RAW image without processing. Not that processing couldn't improve it, but that it should be reasonably good without additional effort.

[reeftool]

Sony is much more than a gadget company. Most of the current cameras on the market have Sony sensors, including Pentax. Sony has been making high end video gear for years. Add to that, they purchased Minolta and they have the experience and legacy that came with Minolta cameras. Ricoh has chosen to keep the Pentax name and is continuing to market cameras and lenses with the Pentax name. Sony has chosen to remove the Minolta name from everything, probably because Minolta is still in the office equipment business and Minolta may have had some say in the matter. All of the lens designs and manufacturing that once was part of Minolta has been absorbed into Sony, just as Ricoh has now absorbed Pentax. To say that Sony has no camera legacy is mistaken.

[Nicolas06]

Sony is much more than a gadget company. Most of the current cameras on the market have Sony sensors, including Pentax. Sony has been making high end video gear for years. Add to that, they purchased Minolta and they have the experience and legacy that came with Minolta cameras. Ricoh has chosen to keep the Pentax name and is continuing to market cameras and lenses with the Pentax name. Sony has chosen to remove the Minolta name from everything, probably because Minolta is still in the office equipment business and Minolta may have had some say in the matter. All of the lens designs and manufacturing that once was part of Minolta has been absorbed into Sony, just as Ricoh has now absorbed Pentax. To say that Sony has no camera legacy is mistaken.

It is just that Sony is a bit geeky on the Camera departement; It allow them to make nice sensors and think of innovative form factor for their camera but their actually throw the minolta echosystem as a side effect.

The thing is, Sony could really do that again in 5 years from now. That's in their DNA. But not everybody like this kind of behavior, in particular when they buy expensive lenses for the echosystem.

Anyway we should not read too far into theses things, this is just gear... Taking photos is more interresting

Their geeky aspect also mean they don't hesitate to make (expensive) lenses with especially huge optical aberations using their jpeg engine to compensate... Not everybody is willing to pay high money for that neither, they fill under corrected lenses should be cheap, not pricey. There many old grumphy guys in photography you know... But they might not be that wrong? Why pay that much for such FE lenses after all other than the fact there is no alternative?

[reeftool]

Anyway we should not read too far into theses things, this is just gear... Taking photos is more interresting

I agree. I have accumulated a fairly large collection of lenses and enjoy using all of them. I'm happy that Pentax will be building a FF camera even though I'm not likely to buy one unless I win the lottery. As for the 150-450, I would be seriously considering one if I didn't already own the Sigma 150-500. There are times when I need every mm of that zoom and I still end up cropping a bit so APS-C is an advantage to most of my photography. While 35mm full frame gets all the hype, the APS sized sensor DSLR's are still the main bread and butter for Nikon and Canon and they don't appear to be adding to their crop sensor lens stable. The Pentax DA lineup matches up pretty well to the Nikon DX and Canon EF-S lines and the Limited primes are something neither has anything close to. It only makes sense that Pentax now has to start rebuilding it's lineup of FF lenses.

[fredralphfred]

. . . The Pentax DA lineup matches up pretty well to the Nikon DX and Canon EF-S lines and the Limited primes are something neither has anything close to. It only makes sense that Pentax now has to start rebuilding it's lineup of FF lenses.

I would argue that the Pentax DA lens line-up is superior to what Nikon and Canon offer. It is, after all, what convinced me to sink money into a Pentax in 2008. What struck me about Canon's and Nikon's line-ups (at the time) were that they were (1) nearly identical, and (2) great if you wanted a large, bulky, and expensive lens every 2mm of focal length. The lenses even looked the same to me. Pentax was doing something different, and they had "enough" coverage of the important 15-100 mm spectrum. I'd still like to see a 135mm, but that's the only hole I can think of. Name four Nikon or Canon primes you can stick in a jacket pocket and go out for a walk. That's a really important feature to me.


In terms of the lenses' speed, there's usually only one stop difference. A large difference, yes, but not show-stopping.


Since Katz-Eye closed, what I really want them to do is come up with a decent aftermarket focusing screen.

[reeftool]

I would argue that the Pentax DA lens line-up is superior to what Nikon and Canon offer. It is, after all, what convinced me to sink money into a Pentax in 2008. What struck me about Canon's and Nikon's line-ups (at the time) were that they were (1) nearly identical, and (2) great if you wanted a large, bulky, and expensive lens every 2mm of focal length. The lenses even looked the same to me. Pentax was doing something different, and they had "enough" coverage of the important 15-100 mm spectrum. I'd still like to see a 135mm, but that's the only hole I can think of. Name four Nikon or Canon primes you can stick in a jacket pocket and go out for a walk. That's a really important feature to me.


In terms of the lenses' speed, there's usually only one stop difference. A large difference, yes, but not show-stopping.


Since Katz-Eye closed, what I really want them to do is come up with a decent aftermarket focusing screen.

Another consideration is that Nikon and Canon APS lens lines are, while not bad, aren't considered their best lenses. They build their best stuff for the FF cameras whereas Pentax builds a high end APS line with their DA Limiteds and DA* lines. That's understandable since Pentax, under previous ownership, had no intention of building a FF camera. It's going to be interesting to see how the lens lineup develops in the next few years.

There are plenty of aftermarket focusing screens around and some are pretty good. The big problem with them is the shims. Pentax won't sell them any more and none of the aftermarket sellers that I'm aware of do so that means spending a few hours screwing around making your own. Katzeye was unique in that they had full support for their customers, even to the point where you could send them your camera and they would install and adjust the screen. You could see how well that went. If you want to read back a few years, you will come across loads of posts on how the Katzeye was way overpriced and you could buy the same thing on Ebay $25. It's sad to see them go. I was a customer.

[jatrax]

I thought I read that Katzeye was back under new ownership?

Also I got focusing screens from Focusing Screen and they came with shims.

Edit: looks like the deal fell through and Katzeye is closing.