[Nicolas06]

I don't agree completely. If you compare to comparable lenses, both focal length and aperture equivalent lenses, the weight and size is in the same ball park. Sometimes a more heavy, other times lighter. Pricing can vary a lot but even there its a slight correleation in equivalencys. Making a larger aperture lens for a smaller format tends to be more expensive. If large sensors where free and camera size didn’t matter the marked would shift significantly towards small aperture large format lenses.

Here is a comparison between 50-135/2,8 lenses for APS-C and 70-200/4 lenses for FF.
Here is a comparison between a 18-55/2,8-4 lens for APS-C and 28-80/3,5-5,6 lenses for FF.
Here are 16-50ish f/2,8 APS-C lenses compared to 24-70 f/4 lenses for FF.

This equivalency comparisons gives you the same field of view and same total light gathering power with the same shutter speeds. But it doesn’t give you the same resolution. Normally the FF option gives you more detail (lppmm or P-Mpix) at comparable settings.

- the 70-200 f/4 are all significantly longer 17cm vs 13cm. This is quite noticable.
- The winers in the 16-50 / 17-50 f/2.8 vs 24-70 f/4 arena is the tamron that is 430g 67mm filters 74x82 vs the Canon f/4 that is 600g, 84x97 and 77mm filters. That quite significant difference. Sony is same size/weight but still 3 time more expensive.

Then find me a 200mm f/4 as small as F135 f/2.8 or a 135mm f/2.8 as small as FA77 f/1.8 or a 70-450 as small and light as a DA55-300. The 85mm f/1.8 is 425g while FA50 f/1.4 is 196g.

The problem isn't that you could find some big APSC lenses that are not much smaller than their FF equivalent, but more to find small and light FF lens that match the light APSC lenses.

[mecrox]

I agree there more to a lens than its max apperture and to me that the annoying part of m4/3 it look like either you have many basic kit lenses or you have the very expensive and bulky 12-40. There nothing in between and the lens isn't going to match the capacity of an f/2.8 for FF anyway.

But if you want a cheap f/2.8 lens, APSC and FF are the best platform for it. Here in france a 17-50 is 200-300€ an a 70-200 600€ from tamron. I don't think the tamron has any quality isse at f/4 the matching equivalent and having f/2.8 in addition doesn't hurt. In term of size/weight, 17-50 f/2.8 and 12-40 f/2.8 are very similar.

You'll asso notice that both the 17-50 f/2.8 from tamron and the 12-40 f/2.8 have the same note on photozone, so it is not like one is wonderfull and the other is terrible.

m4/3 has smaller echosystem and concentrate on smaller bodies and lenses and you pay the 2 aspects. This is not necessarily bad but to be known and so when one compared f/2.8 on APSC and m4/3 I just said it is not the same.

Thanks for that.

I'd guess that the M43 ecosystem is at least as large as that for Pentax (or Fuji, e.g.). And that being able to shoot fairly wide open with some confidence plus 5-stop IBIS is good for at least one and perhaps two stops of ISO, so in a lot of situations things even out in the wash. In practical everyday terms I suspect there is often not as much difference between various formats as folks like to think.

My experience with glass is buy the very best you can afford and try to pass by anything mediocre. Good glass makes a real difference not only in quality but in the whole pleasure of photography. Go second-hand if the cost new is too much. Three fab lenses make for a much better kit than six dodgy ones, I think.

For that reason, I would happily take an excellent but slower lens over one which is notionally faster but in other regards the quality is not there. Having used a 16/17-50mm f2.8 on APS-C for some years, would I buy another one? Nope: in DSLR land at least, the quality is not there imho, but the bulk and inconvenience are. YMMV, etc. (Quality includes things like build, sealing, focus speed as well as IQ and control of flare, aberration, etc.)

[D1N0]

small and light FF lens that match the light APSC lenses.

Like the FA 28-70 F4? It is about as big as a 18-55 Kitlens. And has the same range (a bit shorter). But F4 on FF is Like F2.8 on aps-c

[Simen1]

Then find me a 200mm f/4 as small as F135 f/2.8 or a 135mm f/2.8 as small as FA77 f/1.8 or a 70-450 as small and light as a DA55-300. The 85mm f/1.8 is 425g while FA50 f/1.4 is 196g.

- a 200mm f/4 as small as F135 f/2.8 - The F135 is not an APS-C lens. I don’t know any comparable lenses
- a 135mm f/2.8 as small as FA77 f/1.8 - The FA77 is not an APS-C lens and it should really be an 90/2,8 APS-C lens I should search for. I don’t know of a comparable lens
- a 70-450 as small and light as a DA55-300 - The DA55-300 is an APS-lens but I doubt I will find a 82-450 f/5,6-8,5 FF lens to match it
- The 85mm f/1.8 is 425g while FA50 f/1.4 is 196g - The FA50 is not an APS-C lens. The 375g DA* 55mm f/1,4 is officially an APS-C lens but it work very well on FF, so I don’t consider it comparable.

For the comparison to work, we need comparable lenses. FF lenses vs true APS-C lenses with equivalent focal length and equivalent aperture and more or less the same max magnification and features.

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Last edited by Simen1; 02-24-2016 at 04:20 PM.

[redrockcoulee]

I don't agree completely. If you compare to comparable lenses, both focal length and aperture equivalent lenses, the weight and size is in the same ball park. Sometimes a more heavy, other times lighter. Pricing can vary a lot but even there its a slight correleation in equivalencys. Making a larger aperture lens for a smaller format tends to be more expensive. If large sensors where free and camera size didn’t matter the marked would shift significantly towards small aperture large format lenses.

Here is a comparison between 50-135/2,8 lenses for APS-C and 70-200/4 lenses for FF.
Here is a comparison between a 18-55/2,8-4 lens for APS-C and 28-80/3,5-5,6 lenses for FF.
Here are 16-50ish f/2,8 APS-C lenses compared to 24-70 f/4 lenses for FF.

This equivalency comparisons gives you the same field of view and same total light gathering power with the same shutter speeds. But it doesn’t give you the same resolution. Normally the FF option gives you more detail (lppmm or P-Mpix) at comparable settings.

But for a lot of lenses there is no equivalent lens in as far as light gathering ability goes. If I was to replace my 15DA for example I could with a 22 f5.6 but what are the likihood of a lens being made that is around 22mm 5.6 and of similar quality. If I shoot landscapes and not full aperature why should I even care if the FF and APS-C lenses are the same aperature as I pick for FOV , quality, price and size. The fact of the matter is that I can put together a smaller system in APS-C that fits my needs than I can in FF. And currently only two of my lenses will not fit FF and I use all but those two lenses on my film cameras but when I decide I want to travel as light as possible I can do it more easliy with the K5IIs and lenses than I could with equal type of lenses on FF. I don't normaly care how fast the lense is.

None of my Pentax lenses have the light gathering capacity of my Wollensak f4.5 used on whole plate (6 1/2 by 8 1/2 inch) which is about 35 times the size of the full frame sensor or film. But I never compare total light gathering capacity for one system to the next I choose lenses that work for me and it is mostly similar focal lengths that I use on the multiple systems I do use.

I would be considering the K-1 if I did not use my Hasselblad and large format cameras but I do want a light compact system and when I am going out I can make the K5IIs into that system and at times I would have to leave a Zeiss lens behind if my Pentax lenses were bigger.

I think that Pentax would be foolish to not continue making top end and entry level APS-C cameras for as long as there is a market for them. And most likley eventually two FF cameras as well but I do not think that most people consider their system based on total light gathering capacity but more on price and size.

[Nicolas06]

- a 200mm f/4 as small as F135 f/2.8 - The F135 is not an APS-C lens. I don’t know any comparable lenses
- a 135mm f/2.8 as small as FA77 f/1.8 - The FA77 is not an APS-C lens and it should really be an 90/2,8 APS-C lens I should search for. I don’t know of a comparable lens
- a 70-450 as small and light as a DA55-300 - The DA55-300 is an APS-lens but I doubt I will find a 82-450 f/5,6-8,5 FF lens to match it
- The 85mm f/1.8 is 425g while FA50 f/1.4 is 196g -The FA50 is not an APS-C lens. The 375g DA* 55mm f/1,4 is officially an APS-C lens but it work very well on FF, so I don’t consider it comparable.

For the comparison to work, we need comparable lenses. FF lenses vs true APS-C lenses with equivalent focal length and equivalent aperture and more or less the same max magnification and features.

Remark: when you mix your comment inside a quote please use a color or something, This is terrible to read.

Then, you seems to think if a lens is FF, an APSC body can't use it, that not true. Nothing prevent an APSC user to use an FF lens if it prove usefull to him. So let be more clear:
- FA77f/18 on my K3 provide equivalent field of view and dof control as a 115mm f/2.8. Nearest lenses available on an FF body to match that are DFA100 f/2.8 and F/FA 135 f/2.8 that are much bigger/heavier.
- FA50 f/1.4 on my K3 provide an equivalent field of view and dof control as 75mm f/2.2. Nearest lens matching that is 85mm f/1.8 that is much bulkier.
- I wait to see the 70-450 that are as small as 55-300 and 200mm f/4 as small as F135. All with AF of course.




But I use FF lenses every day on APSC and they are small. Mainly because I can apply the crop factor to the focal length to keep the same framing.

FA77 f/1.8 on APSC is equivalent to 115mm f/2.8 on FF but the 100mm f/2.8 or 135mm are much bigger heavier.

[Nicolas06]

Like the FA 28-70 F4? It is about as big as a 18-55 Kitlens. And has the same range (a bit shorter). But F4 on FF is Like F2.8 on aps-c

28-70 f/4 is much bigger than 18-55 collapsible lens. Again imagine that the guy on APSC actually want to get something small so he will not on purpose get a bigger thing than he has to. I agree the 18-55 is slow so the 28-70 might be better choice but a single lens with bad reviews doesn't make a line up.

Let's imagine you want to put together a complete setup man. I'll not just have an FF + that lens and you know it. Currently I have 5 primes DA15, DA21, DA35 ltd, FA77, F135 and a 55-300 so I expect to have 5 prime and 70-450 or equivalent. I checked twice the weight/size and 50% more expensive.

Imagine the many people that have line up like 17-50 + 55-300 or DA21 + DA40 + DA70 or a 18-300... To get the same reach on FF, they need to go up to 450mm in many case or find tiny pancake lenses at 30, 60 and 105mm on FF. That doesn't exist, like it or not.

[D1N0]

28-70 f/4 is much bigger than 18-55 collapsible lens.

Not a fair comparison. A collapsible lens was never made for FF. Doesn't mean it could not be.
I still have a K-5 so I would not loose any reach at the long end and gain a lot at the short end with my legacy glass. There are always trade-offs. It doesn't matter because aps-c is here to stay and FF has offered us a choice to stay with the brand.

[Nicolas06]

Not a fair comparison. A collapsible lens was never made for FF. Doesn't mean it could not be.
I still have a K-5 so I would not loose any reach at the long end and gain a lot at the short end with my legacy glass. There are always trade-offs. It doesn't matter because aps-c is here to stay and FF has offered us a choice to stay with the brand.

I agree it doesn't matter. I don't want FF, I don't buy it and get APSC body, some want both, some will stick to FF. As long as both camera are available we are fine. That was my point for people saying that there was no more market for high end APSC anymore.

As for fair or not to have a collapsible lens, this is moot point. What count for such matter as how much weight you have in the bag, how large it is and how much your gear make everybody aware of your presence.

For short, I agree there a problem to get fast, sharp WA in APSC, but the best compromize here seems to be Fuji mirrorless and I'am happy with DA15. I'll love a DFA 24 ltd as long as it is small enough, I would consider it for APSC, but I'am pretty sure in practice, the DA15 will remain far smaller and cheaper.

m4/3 sell because the kit lenses + body are quite small and acceptable quality. Many of theses kit lenses are collapsible. This is how the market is.

Starting from 0, I would consider to go m4/3 or more likely Fuji APSC for the size/weight factor. I may still choose K mount APSC. The thing that would make me not take m4/3 is that it start to make a noticable difference in quality and I don't like their choice of lenses. But really APSC vs FF, I don't see the value to get more weight, bulkier, more expensive gear for that small difference in quality.

All in all sensor size is the biggest factor for image quality, gear size and price. So it logical different people will want different compromize. Not 1 size fit all. That's why we have smartphone with 1/2.3", premium compact camera with 1" and the top of digital with MF sensor, more than double the size of an FF...

[Pål Jensen]

For the comparison to work, we need comparable lenses. FF lenses vs true APS-C lenses with equivalent focal length and equivalent aperture and more or less the same max magnification and features.

Equivalent aperture is the same aperture. Everything else is just a misunderstanding of the concept of aperture.
Lenses have in reality never same DOF characteristics or same max magnification, while maintaining the same angle of view, cross formats anyway, so the point is moot. Besides, no one says lenses needs to be DOF equivalent anyway.
The law of reciprocity is totally clear and does not involve DOF at all, in case some are still in doubt. Hence it prohibit the concept of comparing 100ISO to 200ISO cross formats as a rule, as reciprocity gives you freedom to do what you like with the parametres to get the same result (exposure). That is what reciprocity means and has been the fundament for photography since it was invented.

[D1N0]

Equivalent aperture is the same aperture

nope it is not about the actual aperture but about amount of light to the sensor and relative DOF (relative to the size of the frame). That is why 'equivalent' and not 'the same' is used.

[RockvilleBob]

New APSC Pentax by early 2016, using Sony A7000 sensor?

[Doundounba]

New APSC Pentax by early 2016, using Sony A7000 sensor?

I believe the thread summary is "doubtful, but two new APS-C bodies by the end of the year likely". Followed by much APS-C vrs full frame bickering.

[Simen1]

The whole equivalency discussion started with this quote:

FF make thing bigger/heavier and more expensive, including lenses. Like 70-200 vs 50-135.

I just disagree that FF necessarily makes lenses bigger, heavier and more expensive. Its not that simple. The reason FF lenses are lager and more expensive are that customers have higher (other) demands, so the lenses are often not built just to match APS-C lenses. They are built with better specs and that is the true reason the FF lenses are bigger, heavier and more expensive.

@Nicolas: A lens made for FF image circle (IE the FA77/1,8) would be larger, heavier and more expensive then a hypothetical DA77/1,8 with a true APS-C image circle. When comparing size, weight and cost, the image circle size does matter. Thats why I want you to compare with APS-C image circle lenses, not just FF lenses put on a APS-C camera.

@Pål: Aperture equivalency is all about finding an aperture that gives the same DoF and total photons/s on another size sensor. It should be combined with an equivalent focal length to give the same field of view. This is just a mathematical tool to compare sensor-lens systems with each other to predict various image properties. The tool have its use and value when one wants to make informed choices of equipment purchase and a tool to explore and reach for certain image properties. IE you have a selection of cameras and lenses and want to know which combination gives a portrait the least DoF, if that was a goal. Or the least image noise if that was the goal.

[GlennG]

Is there anywhere on the Pentax camera roadmap when the next APS C camera, either KS-2 or K3 II replacement, will be released? I'm thinking long term about a replacement for my K5 classic. Currently thinking APS C, despite all the attention for the K-1, superb though I know that cam will be.


How do you view camera generations? Is the K-3 one generation newer than the K-5, or two generations? I have an unwritten rule that any upgrade should be 2 generations or more, so I don't know if K-3 qualifies in that regard. K-3 seems to be a heck of a good deal now, though. K-5 to K-3 upgraders' consensus is that it is well worth it. But K-5 to K-3 is really only about 3 years newer, and the K-5 was already quite good.


Thanks, Glenn