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Author Topic: the so called minuature formats  (Read 19214 times)
dturina
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« Reply #20 on: September 30, 2005, 07:16:47 AM »
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The notion that a 600mm lens on a D60 is equivalent to a 960mm lens on a 1Ds2 is pure illusion. However, a 600mm lens on a D60 will produce an image of equal quality and FoV after the 1Ds2/600mm image has been cropped in Photoshop to the same size.

Now you might ask, why would one want to crop the 1Ds2 image? Well, if that's your longest lens and you are shooting wildlife there might well be no option. The point here is that nothing would be gained by using a D60 for the same shot. Cropping is cropping, whether it's done by the camera or in Photoshop.
None of this applies to Olympus ZD lenses. The term "cropping" applies to the lenses that draw bigger image circle, only the small central part of which is used. However, imagine a lens that draws a circle twice smaller, but *condenses* all the light and resolution from the large circle and contains it within the smaller. That is actually the case - ZD lenses are at least one full stop faster than the competition, and have twice the resolution, if published MTF charts are to be trusted. So, basically, while APS-C has a problem, 4/3 doesn't. The problem is the sensor; I doubt they'll manage to make a sensor with twice the resolution per surface, to utilize the extreme resolution of the lenses.
Olympus lenses are something different from the APS-C stuff, which usually targets the low end of the market. The Zuikos target the high end, sort of like Leica. They are expensive, but of highest quality. I recently tested a ZD 35-100 f/2 prototype, and it's a jewel. If Olympus can make a fast 12 MP body with image stabilization and good noise performance, it could be a dream system, because, realistically speaking, nobody really needs more than 12MP resolution in a small format camera. It would be enough for weddings, sports, photojournalism and wilidlife; only landscape photographers who used to shoot large format might complain.
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keithrsmith
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« Reply #21 on: September 30, 2005, 08:11:41 AM »
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" Basically a 50mm lens is a 50mm lens because it projects an image circle 50mm in diameter."

As far as I understand it this is not so

"For a thin double convex lens, all parallel rays will be focused to a point referred to as the principal focal point. The distance from the lens to that point is the principal focal length f of the lens."

The whole business of crop factors should be forgotten - the important issues are the angle of view of a lens and how many pixels are in the image (and how good the pixels are).

I agree that if Olympus manage to bring out an E1 replacement with 12Mpix it, coupled with the lenses such as the 150mmF2 etc, will be a great system.

Keith
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Ray
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« Reply #22 on: September 30, 2005, 09:18:32 AM »
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None of this applies to Olympus ZD lenses. The term "cropping" applies to the lenses that draw bigger image circle, only the small central part of which is used. However, imagine a lens that draws a circle twice smaller, but *condenses* all the light and resolution from the large circle and contains it within the smaller. That is actually the case - ZD lenses are at least one full stop faster than the competition, and have twice the resolution, if published MTF charts are to be trusted. So, basically, while APS-C has a problem, 4/3 doesn't. The problem is the sensor; I doubt they'll manage to make a sensor with twice the resolution per surface, to utilize the extreme resolution of the lenses.
I take your point and in the absence of reliable test data I cannot make much of an argument here except to point out one or two anomalies.

The finest and most expensive Zuiko lens for the 4/3rds format is the 300/2.8. This lens is actually heavier than Canon's 300/2.8, slightly more expensive and does not have the benefit of IS. Since the 300/2.8 IS is also one of the finest lenses that Canon produce, if not the finest, I would find it difficult to accept that the Zuiko 300mm would be any more than marginally better.

The notion that a lens designed for a smaller format 'condenses' what might otherwise be a large image circle into a much smaller image circle of inversely and proportionally higher resolution has been debunked by BJL. (And he's the lens expert  .) If I've understood him correctly, he says that beyond about 60mm the image circle increases in proportion to focal length and the telephoto effect is basically achieved by the equivalent of a built-in teleconverter which enlarges the central portion of the image circle with some consequent degradation that we associate with all add-on teleconverters, but clearly not to the same degree.

However, there is a significant factor here in relation to DoF when comparing lenses of different focal length to achieve equal FoV with the different formats; something which BJL keeps harping on, but it seems to me this is only relevant because of current discrepancies in pixel densities between full frame and the smaller formats.

To illustrate this point, let's look at what happens with 2 different formats of the same pixel density, the D60 and 1Ds2, when both are used with a standard 50/1.4 lens.

Conventional wisdom says the D60 will exhibit more DoF at the same aperture provided the shooting distances are different so as to achieve the same FoV. Ie. if I was really impressed with the shallow DoF of the 50/1.4, I'll be slightly disappointed when using that lens on a D60. On the other hand, if I was often disatisfied with the DoF I got with full frame 35mm at f11, I'd be pleasantly surprised at the performance of the D60 at f11.

When dealing with different formats of the same pixel density, it's all smoke and mirrors. There's no DoF advantage of the smaller format. The option is always there, with the larger format, to sacrifice the resolution advantage to achieve equal DoF (and equal resolution) at the same aperture and FoV, through a process of cropping.
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John Camp
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« Reply #23 on: September 30, 2005, 09:58:33 AM »
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Ray,
I think we must be talking past each other, and are simply using "crop" in different ways.

You seem to be arguing (or I may be misunderstanding you) that if you take a 1dsII shot with a 100mm lens, and a D2x shot with a 100mm lens, make prints showing the same FOV at the same print size, you will have essentially the same prints.

I am saying that if you do that, the D2x print will look like it was made from ASA 100 color film, and the 1DsII will look like it was made from ASA3200 color film. (This would not be exact, but you get the idea: the ASA 100 film would be way, way sharper with much better resolution and less noise.)

If you agree with that, then we have no difference; our difference has been purely semantic. I don't, however, agree with your use of the word "crop," although I know it's been used that way by zoom-lens users, who talk about making an "in-camera crop" by zooming in closer to a subject.

For me, a crop has always meant throwing away information captured on a negative or a sensor in the production of a final print. No information is thrown away on an in-camera crop; only the fov changes, and you still get the full resolution that your lens/film lens/sensor system is capable of offering.

JC
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Ray
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« Reply #24 on: September 30, 2005, 10:38:11 AM »
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For me, a crop has always meant throwing away information captured on a negative or a sensor in the production of a final print.

John,
If that's the case then you have not understood the entire 'crop factor' issue as it applies to the APS-C format.

Whether or not you describe the different lens requirements of the Canon D30, D60, 10D, 20D etc as a 1.6x focal length multiplier, or as a 1.6x crop factor is just a matter of semantics. I'm easy with both descriptions. I just don't think one should lose sight of the fact that an APS-C camera attached to a full frame 50mm lens (for example) throws away considerably more picture information than does the full frame camera. And the same applies to any 35mm lens you attach to the APS-C format.

If you define cropping as throwing away picture information, then you've got it by default with the APS=C format.
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Ray
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« Reply #25 on: September 30, 2005, 11:01:34 AM »
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The whole business of crop factors should be forgotten - the important issues are the angle of view of a lens and how many pixels are in the image (and how good the pixels are).

What about the MTF response of the lens at a particular resolution? Do you think that's important? And please tell me what consumer grade cameras you know of that employ a 'thin double convex' lens. I don't consider myself to be an expert on lens design and I'd like to know.
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BobMcCarthy
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« Reply #26 on: September 30, 2005, 11:09:12 AM »
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The whole issue of crop sensors just doesn't ring true the way its discussed. It's as if a crop sensor just gives less.

I would like to offer the comment that "ALL' lenses give excess coverage. My 240mm symmar nearly covers 8x10 at infinity, yet it's rarely used that way. Why, well 8x10's are rare as hen's teeth compared to the 4x5 and secondly the lens changes in character as one focuses. The image circle enlarges as one focuses closer. So we're talking about surplus coverage. The 240 focused on a 8x10 at infinity suffers poor edges and light fall off. Sharpness is less than stellar at the edges(however on a contact print, its still #### good) as sharpness tends to fall off the further from the optical center. Pull the bellows out and the edges clean up nicely.

Using the same lens on a 4x5 is an entirely different issue, sharp edge to edge, plenty of coverage for tilt, shift etc. Its works well because we have "SURPLUS" quality (call it sharpness, resolution, contrast whatever). Using less than full coverage is common to all formats from mini to maxi. Therefore "all" cameras are crop camersa

Quality of a lens in most designs is a series of compromises, certainly cost being one of them and throughout history (mine anyway) we always expected lens quality/capability to fall off in the corners. The other corrolary is the center will be much sharper, in most HQ optics a "surplus" compared to the film/sensor( it took micro fine grain film to get a sense of ultimate resolution) so we were sensor (film) limited.

So as I read the MTF charts on teles and long normals, there is a nice distribution of lens quality, nearly out to the edge of the image circle. So if the lens has enough surplus to get all out of a sensor, what else is needed. Teles work fine for 35mmFF or DX with acceptable lens capability. Other factors dominate that part of the discussion, i.e. weight, aperture, etc.

Wides are another issue. High resolution 35mmFF are on the ragged edge as the sensors are now the limiting factor. It can be acceptable, but Canon doesn't currently have the solution and they are the only purveyer of FF cameras at present. Apparently Zeiss has a good design, at least from what I read, but now we're dealing with stop down metering, adaptors etc. Still it shows what can be done. All at great expense for the customer/fan of FF.

Smaller sensors with optimized lenses can equally/esentially work well. As long as the sensor and lens are designed to coexist well, an equally good solution is available. Wide angle 35mm lenses on Dx lose there wideness so DX lenses MUST be provided.

The point of all this is we are discussing issues already identified and solutions being worked on. It is not Canon (FF) vs Nikon (DX) & Canon (APS-C). Canon is in full frame, entirely due to marketing and image. The dollars generated are a drop in the sea compared to the vastness of their other enterprizes and formats. Pretty effective and many of you all are surely convinced.

Nikon has a more elegant solution from my perspective. High density sensors doing more are on the correct side of Moores Law not reducing the cost of silicon platters and chip yield.

In-camera processing is in it,s relative infancy and will make high density sensors much more capable going forward.

Some ask, why I have switched partys. I have been known to carry a brand C camera for 30+ years.

I like Nikon "Color" in the D2x. I prefer it over the competitors.

I had a ton of FD "L"'s that Canon obsoleted and I enjoy using older mf lenses. (I'm using 30yr old AIS Nikkors now)

The D2x has so much excess sharpness and enlargeablility that I wouldn't even concider a larger format camera at this point, that included FF35mm.

4x5 film still represents the ultimate in image quality at an affordable cost.

And DX will always provide acceptable quality at a lower lost or more features for the dollar.

bob
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Ray
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« Reply #27 on: September 30, 2005, 11:32:21 AM »
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And DX will always provide acceptable quality at a lower cost or more features for the dollar.

Maybe so. But if the price difference gets closer, then the buying patterns change. If I have a choice between a 20D at $1500 and a 1Ds2 at $8,000, I don't have to think too hard. If I have a choice between a 20D and a 12mp 5D at $3000, I'm going to be tempted to buy the 5D. If the price gap narrows further, I'm almost certainly going to buy the full frame. The 5D is already cheaper than the D2X, by the way. We've yet to discover whether it has lower noise at high ISOs.
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BobMcCarthy
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« Reply #28 on: September 30, 2005, 12:32:35 PM »
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What if you had a choice between a $3000 5D (13mpxl) and a $1500 30D (13mpxl). A pro might go for a 35FF but 90% would go for the reduced format.

Or a $2000 35D (13mpxl) but now with some pro features (weatherproof/metering/focus).

Nikon/Sony certainly doesn't have a lock on HD sensors

Bob
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keithrsmith
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« Reply #29 on: September 30, 2005, 01:51:51 PM »
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The whole business of crop factors should be forgotten - the important issues are the angle of view of a lens and how many pixels are in the image (and how good the pixels are).

What about the MTF response of the lens at a particular resolution? Do you think that's important? And please tell me what consumer grade cameras you know of that employ a 'thin double convex' lens. I don't consider myself to be an expert on lens design and I'd like to know.
Agreed the MTF is a major factor - across the whole image plane etc.

the point about focal length is that I don't think it's the size of the image circle, its to do with the distance from the lens to to focal point for any lens construction.

Someone tell me if I'm wrong.

Keith
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Bobtrips
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« Reply #30 on: September 30, 2005, 02:17:17 PM »
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What I did mind in this whole thing, at least watching the Olympus SLR forum on dpreview, is that Michael was again unfairly attacked, as if he insulted a leader of some cult, and now the followers are out for revenge. The similar thing happened to Mike Johnston, and now he stopped writing his columns, which is a great loss for the photographic community. People take cameras way too seriously, it seems.
There's way too much brand/format/medium loyalty.  Far too people are able to discuss issues in a logical and non-emotional manner.  I suspect a lot has to do with the fact that many people have a limited equipment budget, perhaps have pushed their budget to obtain their current gear.

I certainly think that a lot of the earlier film vs. digital anger was engendered by the fact that many people had invested a lot of effort in acquiring shooting and darkroom skills that were now becoming obsolete.

Michael has a tendency to be a 'first responder', is quite visible, and tends to draw a lot of the "Kill the Messenger" fire.  I appreciate his willingness to get out front and take the flack.  I'd hate to see him pull back.

OTOH I appreciate what DPR brings to the table.  First there are the more 'technical' reviews.  Then there's the larger/wider group of participants.  Sure they are more rowdy and sometimes just plain jerks.  (Not that this site doesn't entertain a jerk or two. ;o)  But DPR brings a different type of participant to the table.  I learn lots of stuff from both sites.

BTW, if you feel that someone is really out of line on DPR send Phil a email.  Folks get banned from the site quite frequently for misbehavior.
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BJL
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« Reply #31 on: September 30, 2005, 04:39:43 PM »
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Ray is mostly right that any image you can get with a certain focal length (like 300mm) in one format, you can get about equally as well using the same focal length with a sensor that is larger and yet has the same pixel size, by cropping.

But the image quality will not be the slighter bit better, and ther are downsides to the larger sensor, same focal length approach:

a) Cost.
You are paying for and carrying a more expensive camera.

 Viewfinder crop.
Comparing 24x36 format to DX, EF-S, or Four Thirds, the image that you want after cropping occupies only one half to one quarter of the larger format's viewfinder area. Also, with all current and recent DSLR's, the desired part of the image will be smaller, because teh smaler format DSLR's have higher viewfinder magnification at equal focal length (e.g. 1x @ 50mm for the Olympus E-300 vs 0.72x @ 50mm for all Canon EOS 24x36mm format cameras, film and digital.)

c) Lower sensor resolution (lp/mm).
All 24x36mm DSLR's have lower pixel density than even quite cheap smaller format DSLR's, and the gap has ben steadily growig not decreasing, with teh pixel counts instead getting closer. The 5D is 8.2 microns and the 1DS is over 7 microns, while the 20D is 6.4 microns, the new Sony CMOS sensors are 5.5 microns and the E-300 and E-500 are 5.3 microns. So that cropping from the same focal length will give you far less resolution with the larger format.
Ray will probably just assert that this is going to change, offering no evidnce and ignoring th evidence of trends in the opposite direction.

The inherently lower resolution (lp/mm) or larger format lenses is probably a factor in this leveling out of pixel counts. Many Canon lenses are apparently already getting to be limiting factors at 16MP, while even Four Thirds can easily go beyond that pixel count if needed.

d) Flare control
An optimal telephoto lens designed for a smaller format will be slightly different, in that its lens hood and internal anti-flare baffles will have smaller openings, accepting light form only a narrower angular fild of view. This can reduce flare, particularly if a bright light source is just outside the desired FOV, but within the uncropped FOV of the larger format.

So once again, using a lens designed for the job at hand is likely to have an advantage over the "hack" of using a lens designed for a somewhat different task: forming a larger image on a larger sensor or piece of film.
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BJL
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« Reply #32 on: September 30, 2005, 04:58:12 PM »
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The notion that a lens designed for a smaller format 'condenses' what might otherwise be a large image circle into a much smaller image circle of inversely and proportionally higher resolution has been debunked by BJL.
Ths is slightly out of context. That is mostly true with long enough telephoto lenses like your rather extreme 300mm example. (By the way, why use such an extem example by the way? Why consider the most expensive and low selling of all the new Digital lenses instead of a more typical ones like the Olympus 50-200 f/2.8-3.5?)

On the other hand, some normal to wide lens designs for smaller formats do more or less use this "condensing" approach: they add extra convergence in the rear lens elements, so shrinking the larger image formed by the front elements, with the three effects of
a) reducing focal length, maintaining angular FOV over a smaller image circle
 reducing the aperture ratio, making the lens "brighter". Over one stop brighter if going from 35mm to APS-C, and almost two f-stops if going all the way to Four Thirds.
c) raising the exit pupil height, making the lens more telecentric, and so more compatable with standard modern elecronic sensors.

The new Zuiko Digital 35-100 f/2 seems to be an example, as its design resembles a 50-150 f/2.8 at the front with a 1.4 focal reducer at the back: 35-100 f/2 PRO ED Zoom page
That "50-150 f/2.8" front design could in turn have been created from a 70-200 f/2.8 35mm format design by scaling down by a factor of about 1.4x. Each of those two downsizing steps shrinks the abberations of the putative 35mm format parent design, so such an approach should give this Four Thirds format lens about twice the resolution (lp/mm) of that putative 35mm format parent.
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BJL
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« Reply #33 on: September 30, 2005, 05:02:36 PM »
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There is another reasons for wanting to stop down, and that is to control shutter speed.
For the relatively rare cases when one needs such a low shutter speed that not even minimum ISO can give you, using ND filters seems a far more economical approach than buying a far bigger, more expensive sensor.
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Ray
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« Reply #34 on: September 30, 2005, 09:44:42 PM »
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But the image quality will not be the slighter bit better, and ther are downsides to the larger sensor, same focal length approach:

a) Cost.
You are paying for and carrying a more expensive camera.

BJL,
I don't think anyone has tried to make the point that larger format cameras are not more expensive. This debate has been sparked by a narrowing of the price gap with the introduction of the 5D and a likelihood that the trend will continue. If over all cost and weight are your main concerns then you will be amply served by a plethora of P&S choices that already include a 10 megapixel APS-C sensor.

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Viewfinder crop.
Comparing 24x36 format to DX, EF-S, or Four Thirds, the image that you want after cropping occupies only one half to one quarter of the larger format's viewfinder area.

This is not an insurmountable problem, BJL. Viewfinder attachments for those who wish to simulate a longer focal length could be either optional accessories or included with the camera. Ideally, the larger format viewfinder could contain a number of mattes at the press of a button and a zoom function at the press of another button to fill the viewfinder with any one of the matte sizes.

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c) Lower sensor resolution (lp/mm).
All 24x36mm DSLR's have lower pixel density than even quite cheap smaller format DSLR's, and the gap has ben steadily growig not decreasing, with teh pixel counts instead getting closer. The 5D is 8.2 microns and the 1DS is over 7 microns, while the 20D is 6.4 microns, the new Sony CMOS sensors are 5.5 microns and the E-300 and E-500 are 5.3 microns. So that cropping from the same focal length will give you far less resolution with the larger format.
Ray will probably just assert that this is going to change, offering no evidnce and ignoring the evidence of trends in the opposite direction.

I'm not going to ignore evidence of trends in the opposite direction. I'm far too objective and unbiased for that, BJL  Cheesy .

What I have observed is an over all trend to higher pixel density across all formats without exception and an incessant concern on the part of some photographers that their lenses are not good enough to take advantage of that higher resolving capacity of the higher pixel density sensor.

The D2X demonstrated there's still some resolution advantage to be had from greater pixel density. I therefore think it's likely we will eventually see 32MP full frame sensors. The point has also been raised by yourself that over sampling could be a viable technique of extracting the maximum amount of detail and resolution a lens can offer.

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So once again, using a lens designed for the job at hand is likely to have an advantage over the "hack" of using a lens designed for a somewhat different task: forming a larger image on a larger sensor or piece of film.

Or to look at it another way, the performance of the smaller format might eventually be just a subset of the larger format. There's nothing the smaller format can do that the larger format can't, except be lighter and cheaper, but there's plenty the larger format can do that the smaller format can't.  Cheesy
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Ray
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« Reply #35 on: October 01, 2005, 03:06:41 AM »
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Ths is slightly out of context. That is mostly true with long enough telephoto lenses like your rather extreme 300mm example. (By the way, why use such an extem example by the way? Why consider the most expensive and low selling of all the new Digital lenses instead of a more typical ones like the Olympus 50-200 f/2.8-3.5?)

Why? Because the lenses are so exactly equivalent in all respects and both represent the pinnacle of lens excellence from both companies for their respective formats. When or if pixel density exceeds the resolving capability of both lenses (ie. an oversampling situation exists for both sensors, to obviate the need for an AA filter), then these two lenses will reveal more clearly the differences betweeen the two formats, their advantages and disadvantages. Those who claim there's an inherent price and weight advantage of the smaller 4/3rds format without any sacrifice of image quality might find it ain't so  Cheesy .

I've got no reliable information on the other zoom lenses you've mentioned. There are too many variables. Comparing 'inherent' advantages of different formats by using lenses of unknown, variable or simply different quality, gets us nowhere.

However, there's something to be said for choosing a system to match lenses which you know are impressive. A good lens is like a jewel, something to be treasured, but for me the math simply doesn't add up. Most of those Zuiko lenses might be a cut above their Canon equivalent but to achieve the same image quality as 35mm is capable of, their MTF response has to be at least equal at double the frequency, ie. the 150mm Zuiko prime that produces the same FoV as the Canon 300/2.8, needs to have an MTF response at 60 lp/mm that's as high as the Canon lens at 30 lp/mm, an MTF response at 80 lp/mm that's as high as the 300/2.8 IS at 40 lp/mm and a response at 20 lp/mm that's as high as the Canon lens at 10 lp/mm.

I think that's too much to expect, don't you? - not to mention the additional noise of the smaller 4/3rds pixels if we are comparing equal picture height resolution.
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dturina
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« Reply #36 on: October 01, 2005, 08:33:47 AM »
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Most of those Zuiko lenses might be a cut above their Canon equivalent but to achieve the same image quality as 35mm is capable of, their MTF response has to be at least equal at double the frequency, ie. the 150mm Zuiko prime that produces the same FoV as the Canon 300/2.8, needs to have an MTF response at 60 lp/mm that's as high as the Canon lens at 30 lp/mm, an MTF response at 80 lp/mm that's as high as the 300/2.8 IS at 40 lp/mm and a response at 20 lp/mm that's as high as the Canon lens at 10 lp/mm.

I think that's too much to expect, don't you? - not to mention the additional noise of the smaller 4/3rds pixels if we are comparing equal picture height resolution.


It's difficult for me to read the manufacturer's MTF charts with full understanding, as they seem to measure things at different line pair frequencies. However, we have two MTF charts here,
ZD 150mm f/2

and Canon EF 300mm f/2.8 IS

From what I can read, 150mm f/2 has stunning performance at 60 LP, wide open. I have more difficulty reading the Canon chart, as it isn't as well explained, so I can't really tell. I can tell, however, that they both have excellent edge-to-edge sharpness and insane amounts of resolution.
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Danijel
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« Reply #37 on: October 01, 2005, 08:41:12 AM »
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Or to look at it another way, the performance of the smaller format might eventually be just a subset of the larger format. There's nothing the smaller format can do that the larger format can't, except be lighter and cheaper, but there's plenty the larger format can do that the smaller format can't.


Thats always been true, whether we're talking about

sheet film vs. roll (4x5 vs.2 1/4)

roll vs. cassette (2 1/4 vs 35mm)

digital format (35FF vs DX )

The only difference in the last example is that they share infastructure (lens, focus, metering, flash, etc). I believe they need to be seen in the context of different formats.

Does the format meet your needs and/or customer requirements?

My "only" negative with FF is the lens systems are challenged at the wide end (the format is sensor limited in the center and lens limited at the edges). And there has always been a cost premium for utilizing a larger format. DX Image quality (using the high end D2x example, other DX need not apply) is just as capable at the current time as FF.

There is one more negative, but its not format related, and thats the huge quantity of data we're collecting (storing, manipulating,etc), with both formats reaching a point it's overkill for all typical output with the sole execption of "very" large prints.

We are close to the endgame?

If so, that tends to point at economics, not ultimate capability as the principle driving force.

Bob
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Ray
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« Reply #38 on: October 01, 2005, 11:09:28 AM »
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From what I can read, 150mm f/2 has stunning performance at 60 LP, wide open. I have more difficulty reading the Canon chart, as it isn't as well explained, so I can't really tell. I can tell, however, that they both have excellent edge-to-edge sharpness and insane amounts of resolution.
The Canon charts have the thick lines representing contrast at 10 lp/mm and the thin lines 30 lp/mm. Black are at maximum aperture and blue at f8.

What I see here are thick black lines at virtually 100% MTF on the Canon chart, falling off just a bit towards the edges. This is clearly a better response than the Zuiko 150/2 at 20 lp/mm.

If we take an average of the thin solid black line and thin dotted black line, representing 30 lp/mm at full aperture, we find that it's mostly above 90%, falling below only towards the edges. If we take the better of the two lines at 30 lp/mm, the solid thin line representing sagittal resolution (like the spokes of a wheel), we find that sagittal resolution at 30 lp/mm is actually better than the Zuiko at 20 lp/mm.

What I can say in praise of the Zuiko chart is the meridional and sagittal lines do not diverge as much as in the Canon chart which I believe is indicative of better bokeh and less astigmatism, but the contrast at both 20 lp/mm and 60 lp/mm is simply not high enough for this lens to compete with the Canon 300/2.8. Of course it's a cheaper and lighter lens. It's also a stop faster, so it's got its advantages.
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Ray
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« Reply #39 on: October 01, 2005, 11:57:25 AM »
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Thats always been true, whether we're talking about

sheet film vs. roll (4x5 vs.2 1/4)

roll vs. cassette (2 1/4 vs 35mm)

digital format (35FF vs DX )

The only difference in the last example is that they share infastructure (lens, focus, metering, flash, etc). I believe they need to be seen in the context of different formats.


That sharing of infrastructure is very significant. When the difference in price between a full frame body and an APS-C body is no more than the cost of an average zoom lens, it doesn't make much sense to deprive yourself of the full performance of all your lenses, including increased FoV on your wide angle lenses, for the sake of a few bucks.

However, the 4/3rds system doesn't share infrastructure with another format so I suppose there are better reasons for that format to survive than there are for the 'cropped' 35mm format.
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