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03-04-2016, 06:31 PM   #271
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QuoteOriginally posted by Simen1 Quote
The DA*200 f/2,8 has a FF image circle. An APS-C equivalent would be a 135mm f/2,0 with APS-C image circle. I donít know about any lenses like that, but if it existed I would expect it to be shorter, have the same diameter and weigh almost the same
DA*200/2.8 vs. Samyang 135/2.0 (K-mount version):

Length 134mm vs. 121mm
Diameter 83mm vs. 82 mm
Weight 825gm vs 825gm

So indeed shorter, same diameter, and weighing the same.
The Samyang does have an FF image circle, like the DA*.

03-04-2016, 10:46 PM   #272
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QuoteOriginally posted by Nicolas06 Quote
Pentax has said the DA*200 f/2.8 is really an FF lens and provide support for it on the K1. A DA*200 made for APSC only would be smaller/lighter.
The weight and dia of the lens is set by this formula 200mm/2.8=71mm if they are to make the lens smaller they would be imposing limitation in the performance of the lens

It’s no coincidence that the 200 F2 300 F2.8 and the 400 F4 all fall into the same weight and Dia category It all boils down to one number 100mm
200/2=100mm 300/2.8=107mm 400/4=100

If we use the commonly held belief that a smaller format can use small lens designs we have to look no further than mirco4/3 Olympus M.Zuiko Digital 300mm F4 IS toping the scale at 1270g
or if we take a look at their 70-200 F4 equivalent Olympus Zuiko Digital ED 35-100mm 1:2.0 at 1650g you would think that a camera business based on being smaller could do better

But by the look of what these lenses are capable of is what influenced the size of the lenses, simply put if you want to have fast quality lenses, with resolving power and that are well corrected
they come at the cost of size weight and $ there's no getting around it.

QuoteOriginally posted by Nicolas06 Quote
Compare the 50-135 f/2.8 an APSC design with the various 70-200 f/4... The Pentax manage to be shorter and lighter than the others, even the 70-200 f/4 from Sony that is supposed to have tiny light lenses from the official mirorless
marketing propaganda.
Again it comes down to the formula 200/F4 and 135/F2.8
Canon EF 70-200 mm f/4L IS USM 760g
Canon EF 70-210 mm f/4 605g
Canon EF 70-210 mm f/3.5-4.5 USM 550g
Canon EF 70-200 mm f/4L USM 705g
Nikon AF-S Nikkor 70-200mm f/4G ED VR 850g
Tokina AT-X 70-200mm F4 PRO FX VCM-S 980g
I have a feeling that what a company decides to use for AF motors and the what compromises the designers are going to live with will be the bigger decider on the final weight of the lens more so than the size of format found behind that lens
03-05-2016, 02:24 AM   #273
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When you think of all this reasonning it is a wonder that we manage to have small lenses and small bodies mostly on system with small sensors and big lenses and big bodies on system with big bodies.

When I read all that some explain to me it would appear that it was more or a random choice of the manufacturers and that of course it would have been possible to have medium format and large format system made to fit in the pocket and that we could have achieved a top level high quality system, huge and bulky with very small sensor, courtezy of huge lenses.

So because this is theoretically possible they say, the fact that in practice today, if you want to go smaller the easier way is to get a smaller sensor system is ignored.

They say, but you need to target the same max equivalent apperture that no valid otherwise.

Not really. The whole point of using a bigger format is to get more quality, push the limit so the lens that sell the best for theses format just do that. And the lenses for the smaller format don't have to all target f/0.95 primes or f/1.8 zooms.
03-05-2016, 04:15 AM - 1 Like   #274
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QuoteOriginally posted by DagT Quote
Are you confusing "equivalent focal lengths" with real focal lengths now? A 135mm f/2.0 would be a completely different construction than a 200mm f/2.8. Actually, it would be quite similar to my old 135mm f/1.8 (which is large an heavy), except maybe a litt smaller lenses on the sensor end of the lens because of the reduced sensor size.
I read carefully through my post again, but I donít find where I could have confused something or being to unclear. What exactly do you find confusing?
The old A*135mm f/1,8 is almost the same diameter, shorter and almost the same weight as the DA*200mm f/2,8. An AF f/2,0 APS-C version would probably have almost the same diameter, same length and same weight. All these quite as I would expect. This is yet another empirical indication that I was right about FF lenses not necessarily being heavier then its APS-C equivalents. Many people believe that larger format necessarily means heavier lenses.

QuoteOriginally posted by Bophoto Quote
As i said before, a mirror lens are probable best as a APS lens, but that 400-600 seams to be sharp.
A updated APS fish eye zoom and a new/updated FF fish eye zoom must have CPL and grey filter.
In my opinion DA10-17 needs a CPL filter, but Pentax can repair that mistake in a new HD WR lens, also DA200 and a coming ? 135mm lens
should have a tripod mount or ability to it, think Q cameras...
Why do you think mirror lenses suit APS-C better then FF?
I agree about the gray filter, but I think it would be better to have it in the camera, just like SR.

---------- Post added 03-05-16 at 12:54 PM ----------

QuoteOriginally posted by Nicolas06 Quote
When you think of all this reasonning it is a wonder that we manage to have small lenses and small bodies mostly on system with small sensors and big lenses and big bodies on system with big bodies.
Thats because I/we compare equivalent lenses. Camera systems with smaller sensors have lots of lenses that are worse then this equivalences and very few better ones. Camera systems with larger sensors have lots of lenses that are better then the equivalences, and very few that are worse. For instance, take any of the many f/1,4 prime on a FF camera and you will not find a f/0,7 m43 equivalent. Or take a f/3,5-5,6 normal zoom for m43 and you will not find an equivalent f/7-11 normal zoom for FF. In short, the reason you find more big lenses for big sensor systems are that there are more better lenses.

QuoteOriginally posted by Nicolas06 Quote
When I read all that some explain to me it would appear that it was more or a random choice of the manufacturers and that of course it would have been possible to have medium format and large format system made to fit in the pocket and that we could have achieved a top level high quality system, huge and bulky with very small sensor, courtezy of huge lenses.
I actually have a medium format camera that fits in a jacket pocket. It looks like the UK version on this page, but the markings on my camera is gone so I donít know if its the exact same or what the focal length or aperture is. I guess around 50mm f/3 actual and around 35mm f/2 FF equivalent.

QuoteOriginally posted by Nicolas06 Quote
So because this is theoretically possible they say, the fact that in practice today, if you want to go smaller the easier way is to get a smaller sensor system is ignored.
If you prefer to compare oranges to clementines, then go ahead. You get something smaller, but also less, with the clementine alternative.

QuoteOriginally posted by Nicolas06 Quote
They say, but you need to target the same max equivalent apperture that no valid otherwise. Not really. The whole point of using a bigger format is to get more quality, push the limit so the lens that sell the best for theses format just do that. And the lenses for the smaller format don't have to all target f/0.95 primes or f/1.8 zooms.
Yes, thats just what I try to say. You might choose a smaller camera and smaller lenses to save some weight and money, at the cost of image quality.

03-05-2016, 06:39 AM   #275
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QuoteOriginally posted by Simen1 Quote
Thats because I/we compare equivalent lenses. Camera systems with smaller sensors have lots of lenses that are worse then this equivalences and very few better ones. Camera systems with larger sensors have lots of lenses that are better then the equivalences, and very few that are worse. For instance, take any of the many f/1,4 prime on a FF camera and you will not find a f/0,7 m43 equivalent. Or take a f/3,5-5,6 normal zoom for m43 and you will not find an equivalent f/7-11 normal zoom for FF. In short, the reason you find more big lenses for big sensor systems are that there are more better lenses.
Even "equivalent" don't always match 60-250 vs 100-400 f/5.6, FA77 f/1.8 vs F135 f/2.8, FA50 f/1.4 vs 85mm f/1.8 or on the opposite 35mm f/1.4 vs 50mm f/2... This is because the size of the lens is quite dependant too on the focal length vs the registration distance. Shorter and wide apperture are very difficult to get, same distance or a bit bigger and it get quite small. (FA43, DA40, FA50, FA77...). The futher away you are from the registration distance, the bigger. The 3x4" camera has a small 115mm lens because 115mm not to far from its registration distance.

But people don't necessarily want equivalent. For most photo there no much visible difference bettween APSC, FF, m4/3. Only in some case does it really matter: low light or sport and extremely shallow deph of field. For many people the better/bigger camera isn't that interresting if it is too expensive or simply cumbersome to keep with you.

In the end, the subject, the creativity, the lighting, the composition make or break a photo much more than the gear.

QuoteOriginally posted by Simen1 Quote
If you prefer to compare oranges to clementines, then go ahead. You get something smaller, but also less, with the clementine alternative.
And ironically people still buy clementine even if they found similar or cheaper prices for orange... People don't always want/need/appreciate bigger You'll find people that be willing to pay more to buy and eat clementine that orange.

That the whole thing about compact and m4/3 in term of ligh gathering, dynamic range and DxO mesurement, m4/3 is really behind still it cost often more and people pay for it.
03-05-2016, 02:08 PM   #276
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QuoteOriginally posted by Ian Stuart Forsyth Quote
I have a feeling that what a company decides to use for AF motors and the what compromises the designers are going to live with will be the bigger decider on the final weight of the lens more so than the size of format found behind that lens
Most of my knowledge of the subject comes from the "Intermediate Optics" course I took as part of my Physics Minor, many many years ago. Clearly, the whole subject is much more complicated than many of us would prefer to acknowledge; there is a reason why premier lens designers are special.

Today I took out two lenses that should be roughly comparable: an FD-mount Vivitar 70-210mm f/4.5 that my Mother left behind when she moved to a retirement community, and a currently K-mounted Tamron AdaptAll 70-210mm F4-5.6 that I got as a potential addition to my Q-mount group. The Vivitar weighs 504g, while the Tamron weighs 362g. The Vivitar is 145mm long, while the Tamron is 90 (@70mm) to 120mm (@210mm) long. Obviously, the designers made different choices along the way {and, BTW, the K-mount Vivitar 75-205mm f/3.8 that I pitched because of fungus damage was much larger}

I should also mention that these are the first pictures I took with my newly-acquired Super-Takumar 35mm f/2 lens;
I'm very pleased that they turned out as sharp as they did,

03-06-2016, 02:39 AM   #277
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QuoteOriginally posted by reh321 Quote
... my newly-acquired Super-Takumar 35mm f/2 lens
49mm or 67mm filter thread?
03-06-2016, 11:24 AM   #278
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QuoteOriginally posted by wkraus Quote
49mm or 67mm filter thread?
49 mm

03-06-2016, 11:30 AM   #279
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QuoteOriginally posted by reh321 Quote
49 mm
Thanks! I'm curious about results with the older 67mm version (same vintage as the great 1st version 28mm Takumar), that's why I asked. OT anyway.
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