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11-05-2013, 06:17 PM   #436
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QuoteOriginally posted by Unlimited Quote
Because of different bodies I could not do a direct/fair comparison.
This is what I'm pointing out to. Even DxOMark says comparing lenses goes to a per-system basis only, since you can't just cross-mount lenses on bodies just to evaluate them. The numbers are good on the sites you mentioned are good, true, but then again relevant only to the bodies they were used in. Unless there's a process on measuring lens resolution without using a photographic sensor... (if there is, anyone please correct me on this one thanks)

QuoteOriginally posted by Mistral75 Quote
Drip-proof (WR) is confirmed, DC too (see picture).

"Announced shortly. Released in mid-December"
Nice to hear that. Hope to see official info soon.

as for the hood comments, I hope it's built-in extendable like the FA77's


Last edited by Alizarine; 11-05-2013 at 06:23 PM.
11-05-2013, 06:37 PM   #437
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QuoteOriginally posted by Digitalis Quote
Let me put it this way, using a smaller sensor is not like cutting cylinders* through the lens elements, throwing away the outer perimeter (annulus) of all the glass, and just using "the center of the lens". In fact, the full diameter of the entrance pupil of the lens is always employed, regardless of how tight a sensor crop you take, because the entrance pupil diameter (D) defines the focal ratio (f) in conjunction with the Focal length F (f = F/D). Since cropping doesn't change focal length, and doesn't change the image brightness, it cannot change the entrance pupil size either. So in order to be effective on this lens, the hood should be bigger IMO otherwise even with the hood attached flare will be problematic on both DX and FX format.

* in actuality it is more like a cone going from the annulus of the first element and receding in diameter towards the focal plane. Though this is only a model for when the lens is used at its widest aperture, things change once you start stopping the lens down.
Sure, I get all that. But the viewable field of any given lens is, basically, a conical frustum extending out from the front element and having a vertex angle equal to the lens's angle of view (which is sensor format dependent). Anything within that cone is projected within the image circle circumscribing the sensor.

And because the crop sensor is smaller, the (visible part of the) image circle is smaller, and so the angle of view is narrower, and so is the cone. Thus, one can safely extend the hood until it meets the edge of that cone.
11-05-2013, 06:44 PM   #438
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QuoteOriginally posted by Digitalis Quote
Let me put it this way, using a smaller sensor is not like cutting cylinders* through the lens elements, throwing away the outer perimeter (annulus) of all the glass, and just using "the center of the lens". In fact, the full diameter of the entrance pupil of the lens is always employed, regardless of how tight a sensor crop you take, because the entrance pupil diameter (D) defines the focal ratio (f) in conjunction with the Focal length F (f = F/D). Since cropping doesn't change focal length, and doesn't change the image brightness, it cannot change the entrance pupil size either. So in order to be effective on this lens, the hood should be bigger IMO otherwise even with the hood attached flare will be problematic on both DX and FX format.

* in actuality it is more like a cone going from the annulus of the first element and receding in diameter towards the focal plane. Though this is only a model for when the lens is used at its widest aperture, things change once you start stopping the lens down.
You're thinking way too hard. This has nothing to do with entrance pupils or anything.

Angle of view simply means that incident light within a certain angle of the axis of the lens will be seen by the sensor. Anything occupying that space will be seen by the sensor. A hood optimized for APS-C will be deeper, because it can occupy space that would otherwise be seen by a FF sensor. An FF optimized hood must be shallower than an APS-C optimized hood.

This is extremely easy to prove. Put virtually any APS-C zoom lens with a hood on a FF camera at the widest focal length, and you can actually see the hood in the viewfinder, because it is deep enough to appear in the frame. I just did it right now.
11-05-2013, 06:53 PM   #439
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QuoteOriginally posted by Cannikin Quote
You're thinking way too hard. This has nothing to do with entrance pupils or anything.

Angle of view simply means that incident light within a certain angle of the axis of the lens will be seen by the sensor. Anything occupying that space will be seen by the sensor. A hood optimized for APS-C will be deeper, because it can occupy space that would otherwise be seen by a FF sensor. An FF optimized hood must be shallower than an APS-C optimized hood.

This is extremely easy to prove. Put virtually any APS-C zoom lens with a hood on a FF camera at the widest focal length, and you can actually see the hood in the viewfinder, because it is deep enough to appear in the frame. I just did it right now.
Did it with the K2 and 17-50. Yeah, I can see the hood...

11-06-2013, 12:02 AM   #440
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QuoteOriginally posted by Cannikin Quote
A hood optimized for APS-C will be deeper, because it can occupy space that would otherwise be seen by a FF sensor. An FF optimized hood must be shallower than an APS-C optimized hood.
Take a look at how deep the lens hood is on the FA31mm f/1.8 and FA43 - but you're right, i'm probably over-thinking it (I haven't slept for 33 hours) . But Keep in mind zoom lenses are complex - we don't know all the variables in this particular optical design, which lens groups move for focusing, how far the lens extends and which way it extends as the focal length changes. I agree with the APS-C lenshood can be made longer than what is needed for FX - my sigma 8-16mm f/4.5-5.6 proves this. However, I have an old AF-D nikkor 20-35mm f/2.8 lens from 1996 that has a substantial lens hood on it - with this lens, the deep hood is necessary to be effective at 20mm.
11-06-2013, 12:57 AM   #441
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For example, the hood of my FA35 is rather wide, to accomodate its use for FF, but it's really ineffective when using it on APS-c, unfortunately. So I switched to the DA40 hood (which I use on my M85 also). The difference is hugely noticeable under my situations (I shoot concerts on assignment). The biggest difference is with the M85, however. I had a long, screw on hood that was about 135mm and it was not only bulky, but ineffective. The DA40's hood really helped with the contrast on those old coatings that are prone to flaring. On the FA35, I have better contrast and massively less flare problems. And no noticeable vignetting on either.
11-06-2013, 01:05 AM   #442
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QuoteOriginally posted by ChrisJowett Quote
I agree that the primary issue is DC.
I have 1 lens with an inbuilt motor (Sigma) which I now use more than any other in public due just to noise.
Screw-drive focus is unacceptably noisy and quite frankly out-of-date.
I hate to admit that Canon got it right way back when they launched EOS, but it has paid off. Every Canon lens and every 3rd party lens for Canon is quiet but for we Pentaxians that is something special.
I hope this lens is the thin edge of a DC wedge.
I don't find screw-drive lenses unacceptably noisy at all. I know that using screw-drive focusing allows for smaller lenses, one of the widely-acknowledged advantages of the Pentax system. Most importantly, it also means that lenses are smaller and have one less thing to go wrong. You envy the EOS system but I understand that the most common lens repair in Canon-land is the focusing motor.

I really hope that in-lens motors are kept to bigger, more pro-oriented zooms and fast primes, because I don't want to be lumbered with bigger, more expensive and less reliable lenses.
11-06-2013, 02:11 AM   #443
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QuoteOriginally posted by Jonathan Mac Quote
the most common lens repair in Canon-land is the focusing motor.
Especially with sigma lenses like the 50mm f/1.4...though there are 300mm f/2.8, 135mm f/2 and a 50mm f/1.2 lenses that I have personally experienced issues with.

Thankfully from the patents I have seen the DC motor technology should be considerably more reliable than ultrasonic drive motors.

11-06-2013, 02:21 AM   #444
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i remember the takumars
11-06-2013, 02:52 AM   #445
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QuoteOriginally posted by ElJamoquio Quote
Sounds like the Sigma is very close to your ambient party zoom wishlist.

I wish Pentax would've made it... it would've been slightly smaller I think... but oh well.
So do I but I don't think this is Ricoh priority right now.
They'll first strengthen the brand and market share and profitability but I actually expect them to produce more 'pro' lenses once FF is established.

We'll know more in about a year or about (crossing fingers).
11-06-2013, 03:17 AM   #446
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QuoteOriginally posted by fearview Quote

i remember the takumars
They should skip the silver and just make it available in black and the premium option should be zebra.

11-06-2013, 03:27 AM   #447
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QuoteOriginally posted by snake Quote
(which I use on my M85 also).
Lets see a picture of that.
11-06-2013, 04:11 AM   #448
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QuoteOriginally posted by Digitalis Quote
Take a look at how deep the lens hood is on the FA31mm f/1.8 and FA43 - but you're right, i'm probably over-thinking it (I haven't slept for 33 hours) . But Keep in mind zoom lenses are complex - we don't know all the variables in this particular optical design, which lens groups move for focusing, how far the lens extends and which way it extends as the focal length changes. I agree with the APS-C lenshood can be made longer than what is needed for FX - my sigma 8-16mm f/4.5-5.6 proves this. However, I have an old AF-D nikkor 20-35mm f/2.8 lens from 1996 that has a substantial lens hood on it - with this lens, the deep hood is necessary to be effective at 20mm.
The only thing in lens design that would affect how long the hood can be (beside focal length obviously) is how wide the hood mount is. That is, if the hood diameter is wider, the hood can be made longer and still not intersect the cone of view. Now for a given lens or hood diameter, an APS-C optimized hood will intersect the FF AOV, therefore the FF optimized hood must be made shorter.

Here's a diagram I threw together really quickly in Paint (not to scale):

Last edited by Cannikin; 11-06-2013 at 04:22 AM.
11-06-2013, 04:18 AM   #449
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Best diagram I've seen in a long time that was made in paint...
11-06-2013, 04:44 AM   #450
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QuoteOriginally posted by Jonathan Mac Quote
You envy the EOS system but I understand that the most common lens repair in Canon-land is the focusing motor.
This is a rich one and pretty hard to swallow, considering the years of LULZ that SDM failures are giving us (and counting).
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