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03-15-2013, 08:26 AM   #76
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QuoteOriginally posted by ElJamoquio Quote
Please show me where I attacked you personally. Thanks.


Assumptions: Let's say you want a picture at 50mm equivalent at f/1.4? How much would that cost on the Nikon? The Pentax? What would resolution be on the Nikon? The Pentax?

85mm equivalent?

35mm equivalent? F/1.4? F/2.8?

You didn't want to debate it, so I stopped responding to trolls (like any manual focus 600mm is $12k, much less a f/9 lens) as if they were reasonable arguments.

Throughout this post, I still haven't attacked you personally. I never have. I never will.

Perhaps you're taking your opinion about cameras too personally.
Perhaps I'm not. perhaps you're inability to respond to talking points appropriately is just so rude, I mistake it for personal attacks. It certainly is in a passive aggressive way.

I'll give you one last chance here.

In the long end in an images that will be cropped, it would be counter productive to use a 24 MP FF which would have to be ccopped twice as much as opposed to a pre-cropped 24 MP APS-c. In fact the 24 MP APS-c would provide the same image as a much more expensive 600mm FF lens on FF. Hence there is a level at which FF simply cannot compete with an APS-c camera in terms of cost effectiveness and IQ. Even with a D800, a 24 MP APS-c camera will provide less need to crop using the same lens, making it more efficient for most long range wildlife photography.

That illustrates my point. Your efforts to obscure it are noted... but in the end, are just delaying tactics trying to ignore the obvious.

03-15-2013, 06:52 PM   #77
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QuoteOriginally posted by normhead Quote
I'll give you one last chance here.

That illustrates my point. Your efforts to obscure it are noted... but in the end, are just delaying tactics trying to ignore the obvious.
QuoteOriginally posted by normhead Quote
perhaps you're inability to respond to talking points appropriately is just so rude, I mistake it for personal attacks. It certainly is in a passive aggressive way.

Really, I don't care what you think, but you might want to re-read those two posts put together.

Yes, you can absolutely crop more on a higher pixel density camera. No doubt, no one has ever argued against that. Plus you'll likely have higher framerate. No doubt.

If you're saying that you can crop the K-5 more than a D600, you're right. At the point where that distinction matters, you won't have enough resolution to have a 5-star picture in my book, but if you're going for 3-star stuff, you're all set. Again, that's my experience.

I doubt anyone goes to full-frame worrying about the 3 star pictures. People who read this forum aren't normal camera buyers, of course, and perhaps aren't considering going to full-frame to get more pictures that are so-so.

So I don't think the distinction is particularly relevant.
03-15-2013, 06:55 PM   #78
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QuoteOriginally posted by normhead Quote
the 24 MP APS-c would provide the same image as a much more expensive 600mm FF lens on FF
In terms of image magnification a 400mm f/5.6 lens would be basically the same as a 600mm f/4 lens on FX format, however there are a few key differences in IQ between the two formats: the depth of field will be shallower on the FX format camera. Also a 400mm f/5.6 lens would have to be optically very good indeed to match a 600mm f/4 on FX format, because of the increased image magnification from the APS-C sensor - all optical aberrations will be amplified 1.5X and be more visible than they would be on an FX format sensor. However there is one significant boon to using a cropped sensor over FX format is that the effective magnification at MFD on the 400mm f/5.6 will be greater than the magnification at MFD on the 600mm f/4 on an FX format camera - assuming no one crops their images.

However most wildlife photographers I know myself included, always strive to get as close to our subject as possible regardless of the focal length we are using, and in some occasions a 600mm lens makes this difficult, the closer you are to your subject the greater the DOF Isolation you will achieve. Part of the challenge of Wildlife photography is getting to know your subject and learning how to blend in with your surroundings to get closer and thus produce effective images.


Pentax K7 - Sigma 100-300mm f/4 APO EX DG - 1/250th /f/11 @ ISO 320

I was crouched in the shadows only six feet away from this wren, and because of this: I was able to obtain greater DOF separation between foreground and background - if I had not done this, the subject would have not had enough separation and it would have become somewhat lost in amongst the green and yellows , though the blue colouration of the superb wren would have provided enough colour contrast to make it stand out - though I did not want to be forced to rely on colour contrast alone with this image.

Last edited by Digitalis; 03-16-2013 at 03:41 AM.
03-15-2013, 07:40 PM   #79
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QuoteQuote:
At the point where that distinction matters, you won't have enough resolution to have a 5-star picture in my book, but if you're going for 3-star stuff, you're all set. Again, that's my experience.
Well that's an interesting and bold statement, some would say even arrogant. But you didn't back it up with anything, so I'm completely unable to evaluate it. I've seen some absolutely top rate images taken with K-5s , so, I'm not really sure what you're saying here. maybe you could think of a way to provides some examples. Where is the definition I could use to see what's a 5 star and what's a 3 star image? How do I know you're not just deluding yourself, or applying an unfair rating system?

QuoteQuote:
Also a 400mm f/5.6 lens would have to be optically very good indeed to match a 600mm f/4 on FX format, because of the increased image magnification from the APS-C sensor - all optical aberrations will be amplified 1.5X and be more visible than they would be on an FX format sensor.
This is an interesting argument, one that I'm not entirely comfortable with. Resolutions is measured in Line Width per Picture Height and that is format independent.

If I print black and white alternate lines on an APS-c sensor with 3200 lines, I will have 3200 distinct lines and it will blow up cleanly to what ever size I choose. If I have an FF sensor with 3200 distinct lines , that will blow up to be exactly the same image. Digital does not necessarily degrade because of sensor size. I know that in film days this type of argument would definitely be true, because emulsions weren't laid out in straight lines, and there was an inherent fuzziness because of that. In digital, if the LW/PH is the same, then the resolution is the same, and sensor size is irrelevant.

The only way your comparison would be true would be if in fact the APS-c sensor out resolved the lens. As long as the lens is supplying the sensor with detailed information, it may be that the 600 mm lens is in fact under-utilized. You are comparing two maximized systems, where as the 600 on the FF will quite possibly be capable of producing a lot more resolution than the 400 on APS-c. My suspicion is that the case is that the 400 is still under-utilized on APS-c and the 600 is even more under-uitlized on an FF, because of limitations in sensor density. There definitely will be a point at which your sensor out resolves your lenses and the 600 FF system will out resolve the APS-c system. But with APs-c at 24 MP and FF maxing out at 36 Mp, I think we aren't there yet.

It's still possible that a 24 MP APs-c will equal the 24 MP D600. or be so close that it makes no functional difference.

These are all interesting points, but my feeling is people are locked into pre-digital thought patterns and continue to make mistakes based on misconceptions, things that were true during the days of film, things that will be true again once digital maxes out lens and sensor performance, but things that might not be true at this snapshot in time, when lenses are probably still providing more detail than sensors are capable of resolving.

How else would you explain there being only 200 LW/PH difference between a D3200 and a D600? (2400 and 2600 respectively). The D600 lens is clearly capable of higher resolution, but he sensor doesn't have the density to resolve it,

For there to be a resolution advantage to FF it has to out resolve the APS-c in LW/PH. A pixel is a pixel, digital output is consistent across sensor sizes, in effect the output doesn't care what size the original pixel was. It prints them all the same size. There is no magnification advantage based on pixel size on the recording device. The image produced by the output device is the same, no matter what size the input pixel was.


Last edited by normhead; 03-15-2013 at 07:45 PM.
03-15-2013, 07:56 PM   #80
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QuoteOriginally posted by Digitalis Quote
In terms of image magnification a 400mm f/5.6 lens would be basically the same as a 600mm f/4 lens on FX format, however there are a few key differences in IQ between the two formats: the depth of field will be shallower on the FX format camera.
Just stop down and you'll have the same DOF. You need f/9 or so.
03-15-2013, 09:51 PM   #81
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QuoteOriginally posted by normhead Quote
...

QuoteOriginally posted by Digitalis Quote
In terms of image magnification a 400mm f/5.6 lens would be basically the same as a 600mm f/4 lens on FX format, however there are a few key differences in IQ between the two formats: the depth of field will be shallower on the FX format camera. Also a 400mm f/5.6 lens would have to be optically very good indeed to match a 600mm f/4 on FX format, because of the increased image magnification from the APS-C sensor - all optical aberrations will be amplified 1.5X and be more visible than they would be on an FX format sensor.
Digitalis is right. The only thing a 600 f4 (FF) and 400 f5.6 (aps-c) image would have in common is the FOV.

The 400mm image on aps-c is actually magnified to match that FOV, so the 400 would have to be a significantly better lens than the 600 f4 to match it's image quality. Regarding DOF, the 600 @ f4 on FF would have about 2.3 stops less DOF than the 400 @ 5.6 on aps-c. If you stopped the 600 down one or two stops to match that DOF more closely (if that's what you were after) then the 600 would be performing at probably peak resolution, the 400 still wide-open, expanding the IQ gap even more. You could stop the 400 down as well for more sharpness, but then you might be getting into diffraction or shutter-speed (ISO) concerns on aps-c, as it starts at f/5.6.

Also, a modern $12,000 (really about $9500) VR AF 600 f4 vs. an older MF 400 5.6? Why not compare the Nikon 600 f/5.6 AI or 600 F/4 AI lenses? Very highly rated for IQ, MF like the 400, around $2000 - $2800. Or, get a MF 400 5.6 for about $500 and crop to 16MP on FF (D800). $12,000 to match $500 was a false comparison.






.

Last edited by jsherman999; 03-15-2013 at 09:59 PM.
03-16-2013, 02:11 AM   #82
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QuoteOriginally posted by ElJamoquio Quote
Just stop down and you'll have the same DOF. You need f/9 or so.
On a D800E f/9 is where diffraction begins to lower image quality. No, to level the playing field I am comparing both lenses at f/5.6. A Nikkor 600mm f/4G ED VR on a D800E and a Nikkor 400mm f/2.8G ED VR on a 24mp D7100* - at the same aperture the FX format camera will always have noticeably shallower DOF and greater subject separation. Detail rendering between the lenses will be similar, though the Nikkor 600mm f/4G will have an advantage.

QuoteOriginally posted by normhead Quote
If I print black and white alternate lines on an APS-c sensor with 3200 lines, I will have 3200 distinct lines and it will blow up cleanly to what ever size I choose. If I have an FF sensor with 3200 distinct lines,that will blow up to be exactly the same image
That is only true for a 1000:1 contrast ratio, at lower ratios E.g: 500:1 and lower, lens and sensor performance characteristics will become a limiting factor. Also in print form, the output from a larger sensor will require less magnification in a print, this is the reason why an 8X10 contact prints always looks better than a 8X10 enlargement from 35mm. The same basic principle applies to digital.

QuoteOriginally posted by normhead Quote
The only way your comparison would be true would be if in fact the APS-c sensor out resolved the lens.
This is possible, I have seen some pretty sub-par 400mm lenses in my time. But for arguments sake i'm taking the liberty of assuming that both lenses are built within typical tolerances for lenses of their kind. If the 400mm on the APS-C and FX format 600mm lens I mentioned just happened to both be diffraction limited, super-acromatic lenses with flawless centring then the only visible difference between the APS-C and the FX format camera would be the DOF - however to the best of my knowledge there are only a four lenses suited for 35mm format SLR cameras that posses these optical characteristics, they are exceedingly rare and hideously expensive.

QuoteOriginally posted by jsherman999 Quote
The only thing a 600 f4 (FF) and 400 f5.6 (aps-c) image would have in common is the FOV.
The FOV would be close - but not identical. Most modern super telephoto lenses utilise Internal focusing, and IF lenses experience subtle changes focal length depending on the focus distance they are used. A 600mm lens at MFD would probably be closer to 540mm lens. This effect is referred to in cinematography as lens "breathing" and many cine lens designers go to spectacular lengths to suppress it, which is one of the contributing factors to why cine lenses are so expensive.

Last edited by Digitalis; 03-16-2013 at 10:55 PM.
03-16-2013, 03:30 AM   #83
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I think I'm following this, but wouldn't the need to enlarge the APS-C image for a given print size act to reduce the DOF somewhat (though not to the extent of a 6oomm FF v 400 mm on an APS-C)?

03-16-2013, 06:12 AM   #84
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QuoteOriginally posted by Digitalis Quote
The FOV would be close - but not identical. Most modern super telephoto lenses utilise Internal focusing, and IF lenses experience subtle changes focal length depending on the focus distance they are used. A 600mm lens at MFD would probably be closer to 540mm lens. This effect is referred to in cinematography as lens "breathing" and many cine lens designers go to spectacular lengths to suppress it, which is one of the contributing factors to why cine lenses are so expensive.
Yes, general equivalency FOV comparisons always have to depend on either little focus breathing, similar focus breathing on both lenses, or focus far enough away from MFD where it's not a factor.

The new IF Nikon 70-200 f2.8 VRII really gets out to about 135 at close distances because of that. Really got a few NIkonians cranked.

Last edited by jsherman999; 03-16-2013 at 06:25 AM.
03-16-2013, 06:47 AM   #85
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QuoteOriginally posted by jsherman999 Quote
The new IF Nikon 70-200 f2.8 VRII really gets out to about 135 at close distances because of that. Really got a few NIkonians cranked.
I know, that is why I got the Nikkor 200mm f/2G - primes as a rule do not suffer from breathing as dramatically as zoom lenses do.

Also for those discussing diffraction I will point out that diffraction is a gradual effect. An image on a K5IIs is going to be sharper at f/5.6* than it would be at f/16 - but when having enough DOF to cover the subject is very important, like it is in macro photography - you just have to deal with it.



* 96% of 50mm lenses perform best at this aperture, there are a few rare and unusual lenses that reach their peak sharpness at wider apertures, there are also some 50mm lenses that are so bad they don't improve much no matter how far they are stopped down.

Last edited by Digitalis; 03-16-2013 at 07:16 AM.
03-16-2013, 07:50 AM   #86
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QuoteOriginally posted by jsherman999 Quote
Digitalis is right. The only thing a 600 f4 (FF) and 400 f5.6 (aps-c) image would have in common is the FOV.

The 400mm image on aps-c is actually magnified to match that FOV, so the 400 would have to be a significantly better lens than the 600 f4 to match it's image quality. Regarding DOF, the 600 @ f4 on FF would have about 2.3 stops less DOF than the 400 @ 5.6 on aps-c. If you stopped the 600 down one or two stops to match that DOF more closely (if that's what you were after) then the 600 would be performing at probably peak resolution, the 400 still wide-open, expanding the IQ gap even more. You could stop the 400 down as well for more sharpness, but then you might be getting into diffraction or shutter-speed (ISO) concerns on aps-c, as it starts at f/5.6.

Also, a modern $12,000 (really about $9500) VR AF 600 f4 vs. an older MF 400 5.6? Why not compare the Nikon 600 f/5.6 AI or 600 F/4 AI lenses? Very highly rated for IQ, MF like the 400, around $2000 - $2800. Or, get a MF 400 5.6 for about $500 and crop to 16MP on FF (D800). $12,000 to match $500 was a false comparison.

.
Do you guys even read what I write? ....

If both lenses are sharp, but the 600 mm on full frame is producing enough resolution to dramatically out resolve the sensor.. then the 400 will do just as well as the 600 because the sensor doesn't have small enough pixels to use the available resolution. You continue to ignore the probability that at current MPs, sensors are receiving more information than they are using.

Theoretically in a perfect world, it would be correct (what jsherman posted). Practically with currently available gear, it's very likely the 600's resolving power is wasted. So is the 400's, just the 600 on FF is wasteing more.

How will we know when sensors catch up with lenses? Increasing sensor resolution will stop increasing MTF numbers. So far that hasn't happened, so far every increase in MP has brought a diminishing but measurable increase in MTF.

My musings are based on the limits of modern technology, not the as yet un-achieved theoretical potential of imaginary systems.

Last edited by normhead; 03-16-2013 at 08:19 AM.
03-16-2013, 08:12 AM   #87
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QuoteOriginally posted by Digitalis Quote
On a D800E f/9 is where diffraction begins to lower image quality. No, to level the playing field I am comparing both lenses at f/5.6. A Nikkor 600mm f/4G ED VR on a D800E and a Nikkor 400mm f/2.8G ED VR on a 24mp D7100* - at the same aperture the FX format camera will always have noticeably shallower DOF and greater subject separation. Detail rendering between the lenses will be similar, though the Nikkor 600mm f/4G will have an advantage.
A more level playing field would be a D600 (24 MP) at f/9 compared to a D7100 at f/5.6, or a D800 downsampled to 24MP, etc.

The same aperture is never a level playing field across different formats. Compare them if you want but in my experience there is no reason to.
03-16-2013, 10:10 AM   #88
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QuoteOriginally posted by ElJamoquio Quote
The same aperture is never a level playing field across different formats
It can be if the ISO and shutter speeds are maintained. The aperture controls the level of intensity of light striking the sensor, the shutter controls the length of time the sensor is exposed to light, and the ISO controls how sensitive the sensor is to light. I hate it when people say that there is greater density of light hitting the FX format sensor compared to an APS-C sensor - well, for starters photons are massless* :. they do not have density. However photons do have intensity which is measurable and quantifiable. Providing the registration distance for the F mount is maintained f/5.6 is f/5.6 regardless of how small - or how big the sensor the image is being projected on.

* As far as current scientific knowledge is concerned.
03-16-2013, 01:53 PM   #89
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QuoteOriginally posted by Digitalis Quote
I hate it when people say that there is greater density of light hitting the FX format sensor compared to an APS-C sensor - well, for starters photons are massless* :. they do not have density.
Mass density is the most common use of density but it certainly is not the only common/accepted use of 'density'.
Density (disambiguation) - Wikipedia, the free encyclopedia


QuoteOriginally posted by Digitalis Quote
It can be if the ISO and shutter speeds are maintained.
That produces two different pictures, as you've noted, because of the difference in depth of field.

If you stop down a stop or so, though, the same amount of light hits two differently-sized sensors, and the depth of field is the same between the two pictures. You're producing the same picture in either format.
03-16-2013, 09:00 PM   #90
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QuoteOriginally posted by ElJamoquio Quote
If you stop down a stop or so, though, the same amount of light hits two differently-sized sensors, and the depth of field is the same between the two pictures. You're producing the same picture in either format.
Yes it is possible to duplicate the DOF of an APS-C format camera on FX format - but that defeats the purpose of using a bigger sensor in the first place. Lenses have to be better on APS-C format to be able to duplicate the shallower DOF obtained on FX format because of the wider apertures needed to compensate for the smaller sensor format.
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