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05-11-2010, 12:59 PM   #16
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ISO digression from 135 club thread

The reason ISO matters when comparing a lens on one camera to a different lens on a different cameras is that we are *not* just comparing lenses - we're comparing *cameras*. ISO 1600 on a K1000 is just not the same thing in terms of image quality as ISO 1600 on a K-x - not even close. So a lens that does f/2.8 and therefore allows a given shutter speed at ISO 1600 is quite simply a less useful lens for low light on the K1000, because the K1000 exacts a much higher penalty for shooting higher ISO. One can choose to ignore IQ or not ignore it. I choose not to, because I care about IQ.

05-11-2010, 09:24 PM   #17
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QuoteOriginally posted by Marc Sabatella Quote
The reason ISO matters when comparing a lens on one camera to a different lens on a different cameras is that we are *not* just comparing lenses - we're comparing *cameras*. ISO 1600 on a K1000 is just not the same thing in terms of image quality as ISO 1600 on a K-x - not even close. So a lens that does f/2.8 and therefore allows a given shutter speed at ISO 1600 is quite simply a less useful lens for low light on the K1000, because the K1000 exacts a much higher penalty for shooting higher ISO. One can choose to ignore IQ or not ignore it. I choose not to, because I care about IQ.
That is the gospel truth, Marc. If I got the results on ISO 1600 film that I get from my K10d at ISO 1600 I would be leaping with joy.
05-11-2010, 10:40 PM   #18
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QuoteOriginally posted by Marc Sabatella Quote
The reason ISO matters when comparing a lens on one camera to a different lens on a different cameras is that we are *not* just comparing lenses - we're comparing *cameras*. ISO 1600 on a K1000 is just not the same thing in terms of image quality as ISO 1600 on a K-x - not even close. So a lens that does f/2.8 and therefore allows a given shutter speed at ISO 1600 is quite simply a less useful lens for low light on the K1000, because the K1000 exacts a much higher penalty for shooting higher ISO. One can choose to ignore IQ or not ignore it. I choose not to, because I care about IQ.

So a slower lenses is more useful in that situation? (that's rhetorical) However, f2.8 is still f2.8 whether you shoot ISO 25, 64, 100, 125, 200, 400, 800, 1600 or push process 3200 (or pull process). Plus, many people actually push 400 speed film to 800 or 1600 so you overlooked the fact that there is more than 1 way to get to 1600. Besides, if I wanted a faster shutter speed, I'd go with the SuperProgram or Me F or MZ-3. Besides, it isn't always about the shutter speed but low light. Finally, in the recent threads this has come up, it has been about fast lenses and not about the effects of ISO whether digital or film.

All that aside, my argument has been that a fast fifty is a fast fifty regardless if its on a digital body or film body independent of IS0.

My real argument the 1st time this came up in the A 50mm f1.4/FA 50mm f1.4 is that to compare lenses, it is good to keep the camera the same. Likewise, if you compare film or sensors, it may be good to keep the lenses the same.
05-12-2010, 04:58 AM   #19
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QuoteOriginally posted by Blue Quote
So a slower lenses is more useful in that situation? (that's rhetorical) However, f2.8 is still f2.8 whether you shoot ISO 25, 64, 100, 125, 200, 400, 800, 1600 or push process 3200 (or pull process). Plus, many people actually push 400 speed film to 800 or 1600 so you overlooked the fact that there is more than 1 way to get to 1600.
Those that shoot at 1600 however don't really care about the IQ of the lens. For 400 and higher, you can essentially shoot through a tin can. I for one never ever push film. The increase in contrast puts me off and the increase in grain will make the advantages of a particular lens in terms of sharpness disappear.

My basic reasoning with telephoto lenses is this: For one, you never have to shoot them wide-open for the purpose of a shallow depth-of-field. f/4 or f/5.6 are under virtually all circumstances shallow enough. I therefore stop them down a stop or two to get close to their optimum aperture as far as sharpness and rendering are concerned. With a slower lens and kind of film I prefer (in the ISO 25 to ISO 125 range) this will often put you right on the 1/focal-length demarcation line. Two thirds or half a stop slower will push you beyond. With film bodies and their lack of shake reduction, hand-holding a 135mm with shutter speeds below 1/125 sec is very hard. If I shoot vertically, I generally lose one additional stop anyway because I find it more difficult to keep this configuration steady.

This is the reason why my Sears 135mm f/2.8 gets so much more use than my Pentax 135mm f/3.5 even though the latter is a little smaller and might even have a slightly better rendering wide-open. It is however not as good as the Sears at f/4.

Cheers,
Tassilo

05-12-2010, 06:32 AM   #20
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when I look at lens speed, and high ISO I have a different approach, somewhat out of necessity.

I have shot a ton at iso 1600 and ISO 3200 wide open at F2.8 using my sigma 70-200F2.8 or at F2.5 with my SMC 135 F2.5.

WHen I am in a low light high iso situation, it is usually one where I need shutter speed, and am not allowed a flash. (Dance, stage performances etc). As a consequence I shoot a lot wide open.

for me, there is just no substitute for a lens that performs very sharp at maximum aperture.

Both my Sigma APO 70-200F2.8 and my SMC 135F2.5 are stellar performers wide open and I use them that way. For me it is not about comparing a full frame film camera with a ASP-C DSLR and the difference in quality at high ISO, I could care less. It is about getting the shot period.


Now on the other hand, when you are out in the sunshine with ISO 100 film, and comparing a 135 F3.5 on a dslr to a 200F4 on a film body, you may actually be comparing very similar image quality and resolution (depending on the film quality and whether this is a 6 or 10 mp camera)

Here lens speed does not matter at all you need the same shutter speed on both cameras to get the same sharpness from motion blurr, and the lenses are close enough in aperture that even wide open they will yeild similar results.
05-12-2010, 08:56 AM   #21
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QuoteOriginally posted by vparseval Quote
Those that shoot at 1600 however don't really care about the IQ of the lens. For 400 and higher, you can essentially shoot through a tin can. I for one never ever push film. The increase in contrast puts me off and the increase in grain will make the advantages of a particular lens in terms of sharpness disappear.

. . .
I probably do more pulling than pushing film. However to say that film guys don't care about IQ because they may be shooting high ISO is preposterous.

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QuoteOriginally posted by vparseval Quote
. . .
This is the reason why my Sears 135mm f/2.8 gets so much more use than my Pentax 135mm f/3.5 even though the latter is a little smaller and might even have a slightly better rendering wide-open. It is however not as good as the Sears at f/4.

Cheers,
Tassilo
I posted some examples from the Sears lens you mention in the 135mm club thread. For 15 years, it was my 135mm lens. I still have it and an identical spare.
05-12-2010, 10:11 AM   #22
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QuoteQuote:
Marc Sabatella: ISO digression from 135 club thread

The reason ISO matters when comparing a lens on one camera to a different lens on a different cameras is that we are *not* just comparing lenses - we're comparing *cameras*. ISO 1600 on a K1000 is just not the same thing in terms of image quality as ISO 1600 on a K-x - not even close. So a lens that does f/2.8 and therefore allows a given shutter speed at ISO 1600 is quite simply a less useful lens for low light on the K1000, because the K1000 exacts a much higher penalty for shooting higher ISO. One can choose to ignore IQ or not ignore it. I choose not to, because I care about IQ.
Lots of good points and good you bring them up here.
05-12-2010, 01:10 PM   #23
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05-12-2010, 01:36 PM   #24
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QuoteOriginally posted by Blue Quote
So a slower lenses is more useful in that situation? (that's rhetorical)
You may have meant it to be rhetorical, but since the answer is not what you seem to be assuming it is, I need to answer:

A slower lens on APS-C digital can be more useful than a faster lens on film, yes, for exactly the reasons I laid out. Yes, you can shoot ISO 1600 on both and get faster shutter speeds with the fast lens on film, but if you care about IQ, you wouldn't *not* be shooting ISO 1600 film (or, put another way, if you are OK with ISO 1600 film, then you should be equally OK with shooting ISO 6400 or higher on APS-C digital).

QuoteQuote:
Plus, many people actually push 400 speed film to 800 or 1600 so you overlooked the fact that there is more than 1 way to get to 1600.
I didn't overlook that fact; it just isn't relevant. The IQ of the image will be roughly the same whether shooting ISO 1600 film or push processing ISO 400 film. Either way, it's going to be a lot worse than ISO 1600 on APS-C digital. Similarly, there is more than one way to get ISO 1600 on digital, but in the end, it doesn't really matter which way is chosen. There is no way around the basic fact of life when comparing film to APS-C digital - you've got at least a two stop advantage with digital to play with.

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Besides, if I wanted a faster shutter speed, I'd go with the SuperProgram or Me F or MZ-3. Besides, it isn't always about the shutter speed but low light.
I'm really struggling to understand what you mean by these statements. How would a different film camera help you get faster shutter speeds in low light? Low light is what we're talking here, and the reason shutter speeds come into play is that we're often struggling to get shutter speeds fast enough to avoid blur. The maximum shutter speed of the camera is irrelevant here - we're talking about situations where one is struggling to make 1/60", not wondering whether the camera happens to be capable of 1/6000" or not.

QuoteQuote:
Finally, in the recent threads this has come up, it has been about fast lenses and not about the effects of ISO whether digital or film.
True, the other thread (singular) where this issue came up was different. Very different, actually - not the same claims being made *at all*, and not even the same issues involved. Just some of the same terms. I think you were basically misunderstanding the point being made there, and you're definitely very much misunderstanding the point being made here if you're thinking of it as being similar.

In the other discussion, no one was claiming that raising ISO actually made the slower lens *equivalent* to the faster lens. Just that in *practical* terms, a half stop difference isn't that *significant* most of the time, because whatever shutter speed you think you need to achieve in order to get a successful shot can be achieved with either lens, with only a half stop difference in ISO (meaning the IQ with the slower lens will only be half a stop worse). That is, in that other thread, we're admitting that the slower lens will give worse IQ for the same basic image, but only a *little* worse. Whereas in this thread, I'm pointing out a slower lens on APS-C digital can actually give *better* IQ for the same basic image than a faster lens on film.

Last edited by Marc Sabatella; 05-12-2010 at 01:44 PM.
05-12-2010, 02:00 PM   #25
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QuoteOriginally posted by Douglas_of_Sweden Quote
Thinking for myself: Me wondering if a moderator could give himself an infraction for not respecting the subject of the thread despite being politely asked...
He could, but is wondering if having now moved everything over to this new thread will serve as sufficient penance.
05-12-2010, 03:12 PM   #26
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In my days of shooting film I shot exactly 6 rolls of ISO 1600 from '85 to 2008. Of those only 2 came out with any useable pictures. Those were of Christmas lights back in the late 80's in Omaha. All others generally had problems usually with the color but also the grain on 4x6 prints. I haven't tried anything above 800 on my K100D but so far it has done really well, much better at 800 than ISO 800 film which became my 'low light' choice in my film years. If I couldn't catch the image with natural light on 800 speed I got out a flash unit.
05-12-2010, 04:41 PM   #27
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With all due respect, Marc, I think that adding a "digital vs film" dimension to the "changes in focal lengths and aperture" + "change in format" dimensions isn't helpful. Your points apply independently of format comparisons.

Regarding the original "135/2.8 on APS-C == 200/2.8 on APS-C" discussion: It is pretty easy to see that this equivalence doesn't hold in terms of DOF. The DOF with a 135/2.8 on APS-C is not as shallow as with a 200/2.8 on FF. That alone should suffice to make the reference to a virtual 200/2.8 invalid.

The difference in speed is less easy to grasp but it exists. Yes, a f/2.8 lens stays an f/2.8 lens independently of the format but the same is true for the focal length, it doesn't change either. If anyone acknowledges that a 135mm lens yields different AOVs on different formats then they should also acknowledge that changes in DOF and speed occur as well.

Forget about the APS-C format and consider an FF shooter who uses a 135/2.8 lens to take an image and than crops the latter to yield the image that a 200mm lens would have taken. Do you think he'll get the same noise performance compared to having taken the same image with a 200/2.8? Of course not. And this is not the result of losing resolution because of the cropping and subsequent enlargement. The real reason is that less total light is used for the cropped out part of the 135/2.8 shot compared to the 200/2.8 shot.

BTW, this makes another point: Smaller formats are more resolution hungry. To yield the same sharpness from a 135mm crop that a 200mm shot would have given, the 135 lens needs to be crop-factor times sharper, i.e., in our example ~1.53x sharper. Or put differently, the 135/2.8 has to be so sharp that it matches the sharpness of a 200/2.8 even if you put a (perfect) 1.5 teleconverter behind it.

Let's cherish our old lenses for what they are on APS-C but let's abstain from making invalid comparisons on what they might be equivalent to on an FF camera.
05-12-2010, 08:28 PM   #28
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QuoteOriginally posted by kacansas03 Quote
In my days of shooting film I shot exactly 6 rolls of ISO 1600 from '85 to 2008. Of those only 2 came out with any useable pictures. Those were of Christmas lights back in the late 80's in Omaha. All others generally had problems usually with the color but also the grain on 4x6 prints. I haven't tried anything above 800 on my K100D but so far it has done really well, much better at 800 than ISO 800 film which became my 'low light' choice in my film years. If I couldn't catch the image with natural light on 800 speed I got out a flash unit.
I think I have purchased 1 roll of 1600 film in the past 28 years. That wasn't my argument. Unfortunately, this aperture argument in 2 different threads have gotten into the debate about high ISO. That hasn't been my concern. The fact is an f1.2 lens is an f1.2 lens at 64 ISO or 3200 ISO regardless if its a film camera or if its a digital camera. In the most resent thread, it was an f2.8 lens.

Edit: Did you even look at the link I posted?

Last edited by Blue; 05-12-2010 at 09:13 PM.
05-12-2010, 09:11 PM   #29
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QuoteOriginally posted by Marc Sabatella Quote
You may have meant it to be rhetorical, but since the answer is not what you seem to be assuming it is, I need to answer:

A slower lens on APS-C digital can be more useful than a faster lens on film, yes, for exactly the reasons I laid out. Yes, you can shoot ISO 1600 on both and get faster shutter speeds with the fast lens on film, but if you care about IQ, you wouldn't *not* be shooting ISO 1600 film (or, put another way, if you are OK with ISO 1600 film, then you should be equally OK with shooting ISO 6400 or higher on APS-C digital).

I didn't overlook that fact; it just isn't relevant. The IQ of the image will be roughly the same whether shooting ISO 1600 film or push processing ISO 400 film. Either way, it's going to be a lot worse than ISO 1600 on APS-C digital. Similarly, there is more than one way to get ISO 1600 on digital, but in the end, it doesn't really matter which way is chosen. There is no way around the basic fact of life when comparing film to APS-C digital - you've got at least a two stop advantage with digital to play with.



I'm really struggling to understand what you mean by these statements. How would a different film camera help you get faster shutter speeds in low light? Low light is what we're talking here, and the reason shutter speeds come into play is that we're often struggling to get shutter speeds fast enough to avoid blur. The maximum shutter speed of the camera is irrelevant here - we're talking about situations where one is struggling to make 1/60", not wondering whether the camera happens to be capable of 1/6000" or not.



True, the other thread (singular) where this issue came up was different. Very different, actually - not the same claims being made *at all*, and not even the same issues involved. Just some of the same terms. I think you were basically misunderstanding the point being made there, and you're definitely very much misunderstanding the point being made here if you're thinking of it as being similar.

In the other discussion, no one was claiming that raising ISO actually made the slower lens *equivalent* to the faster lens. Just that in *practical* terms, a half stop difference isn't that *significant* most of the time, because whatever shutter speed you think you need to achieve in order to get a successful shot can be achieved with either lens, with only a half stop difference in ISO (meaning the IQ with the slower lens will only be half a stop worse). That is, in that other thread, we're admitting that the slower lens will give worse IQ for the same basic image, but only a *little* worse. Whereas in this thread, I'm pointing out a slower lens on APS-C digital can actually give *better* IQ for the same basic image than a faster lens on film.
I should have expanded on the shutter speeds. 1st off, I no longer have a K1000 unless I count my wife's. However, on a sunny summer day in Florida, 400 speed film can be used for action shots at volley ball games etc. I didn't specify just low light.

Neither thread had anything to do with anyone claiming 1600 ISO film had better IQ than 1600 on a digital sensor. Although, its been my observation that film people often talk about the graininess or the sharpness rather than IQ directly.

Both threads had to do with aperture speeds, 1 comparing 2 Pentax f1.4 lenses and the other comparing a 135mm f2.8 lens on 135 film and aps-c. And frankly, a half a stop can be significant given that the next largest full stop is 2x the light the previous stop. Plus, its not linear from f64 to f1. I wonder why EV controls were added to cameras. (also rhetorical).

In my current film stash, I have 110, 135, 127, 120, and 220. The fastest I have in any of it is 400 but over half of it is 160/200 with the rest evenly split up between 64, 100 and 400. 99.9% of my night and low light shooting is with digital and often set at 400 and 800. The beauty of shooting RAW is that it allows to under expose by 1 or 2 stops in action sequences. Its sort of like pulling.

Regardless, an f2.8 135mm lens is a f2.8 135mm lens. When an optics lab tests for resolution etc., they are going to use the same film and/or sensor under the same conditions when comparing samples from a lot or different models. Different ISO speeds wouldn't introduce another variable into the test. Like wise, if a film or sensor is tested, the same lens would need to be used to help stabilize variability.
05-13-2010, 08:51 AM   #30
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QuoteOriginally posted by Blue Quote
I probably do more pulling than pushing film. However to say that film guys don't care about IQ because they may be shooting high ISO is preposterous.
Which isn't what I said obviously. :-) I said that film guys don't care about specific aspects of IQ since those are obliterated by their choice of high-speed film. Sharpness of the lens would be one of those. More often than not it's a compromise. An image shot on 1600 or 3200 film because light was that low will exhibit infinitely superior IQ than any of my non-existing shots under similar circumstances.

QuoteQuote:
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That would be one of those examples where the highest sensitivity was required. Yet I insist that a lesser lens could have been used with no adverse effect on IQ. With film, the particular choice of film always trumps the lens: Efke KB25 shot with a cheap Takumar 135mm f/2.5 will yield results orders of a magnitude sharper than a K 135mm f/2.5 shot on TriX.

QuoteQuote:
I posted some examples from the Sears lens you mention in the 135mm club thread. For 15 years, it was my 135mm lens. I still have it and an identical spare.
Very justifiably so. It's almost flawless on a film body. I have four of those, although only one of them actually has a working aperture. :-)

Cheers,
Tassilo
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