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07-04-2012, 11:00 AM   #136
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Anybody has a scientific article to offer that explains why FF sensors offer better IQ over smaller sensors like APS-C? I can't seem to grasp why that'd make sense.
There are so many other factor that go into making an image besides just sensor size... new sensors out perform older sensors... etc. I'm not sure you can state that except in a very narrow theoretical way. You can probably say a D800 out performs what ever is out there right now, at least that's the buz... but it's pretty much guaranteed APS-c will strike the next blow. And even on the D800, it's the MP half of the equation that makes it more attractive, not the fact that it's FF. I find it somewhat humorous that the higher pixel density for the same MP used to be the supposed reason APS-c didn't stack up to FF in noise and low ISO etc. Now that the D800 has a higher pixel density than a k-5... I don't see people applying the formula in favour of APS-c. It's obviously not as straight forward as people would have you believe.

07-04-2012, 11:06 AM   #137
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D800 has the same pixel density i believe norm

and you're right it's anything but straightforward.
07-04-2012, 12:30 PM   #138
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QuoteOriginally posted by normhead Quote
. And even on the D800, it's the MP half of the equation that makes it more attractive, not the fact that it's FF.

I disagree. It's really both, but the majority of improvement is just having a larger surface area.
07-04-2012, 01:17 PM   #139
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I read both the "True reasons for FF" and "Camera Equivalences" articles and am still baffled about something...

The article mentions
QuoteQuote:
But within a given equivalence class of cameras (a given image quality, so to speak), making the sensor smaller reduces sensor cost and increases lens cost.
isn't the legendary Canon 85L a FF lens, yet it's still twice as expensive as one of the best lens Pentax has to offer that might rival the IQ of the 85L (the FA31 Ltd)? Isn't the FA31 a FF lens as well, since it was developed for FF film cameras in the first place?

Not trolling or arguing, I'm really just trying to wrap my head about the price discrepancy between Canikon's top glass (like the 85L, or Nikon's 24-70) versus Pentax's top glass, especially considering Canikon's top glass is marketed at professionals who most likely shoot FF.

07-04-2012, 01:54 PM - 1 Like   #140
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If you wanted APS-C glass that matched the FF glass, it would be even more expensive...


and if you wanted to match the DOF&SNR, too, it'd be crazy. The 85 1.2 would need to be a 50mm 0.75 on Canon. The 31mm f/1.8 would need to be a 20mm f/1.2. Obviously those lenses don't exist, although in theory they could, but they would be huge and cost more than my car. OK, tons of lenses cost more than *MY* car, but it would probably be more expensive than your car, too....

...and those lenses still wouldn't have the resolving power that a FF lens does.


The bottom line is that the before you go to the ultra-top-glass, it makes more sense to go to FF... which is why most top glass is FF, especially with makers who continue to produce FF.
07-04-2012, 02:21 PM   #141
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QuoteOriginally posted by ElJamoquio Quote
If you wanted APS-C glass that matched the FF glass, it would be even more expensive... .
But the FA31 isn't APS-C glass, it was built with FF sensors in mind.
07-04-2012, 02:36 PM   #142
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QuoteOriginally posted by FrancisK7 Quote
But the FA31 isn't APS-C glass, it was built with FF sensors in mind.
Yes.

Let's start over...

If you want APS-C glass that matched a FF Sensor + 31mm f/1.8, the APS-C would be a 20mm f/1.2, and would be much larger, much heavier, and much, much, more expensive, think $10k plus, and probably still wouldn't match the resolution of the FF + 31mm f/1.8.

If instead, you want a FF lens to 'exactly' match the APS-C + 31mm f/1.8, you'd design a 50mm f/2.8. Of course, you wouldn't REALLY do that, because 50mm's are so cheap and light anyway, much cheaper and lighter than the 31mm, so instead you'd design a 50mm f/1.7 or f/1.8, and again the FF lens would be cheaper, lighter, smaller, and in this case, much faster, too, allowing better AF/quicker shutter/shallower DOF if desired.


Yes, the 31mm was designed as a FF lens. It's a great lens. It's also very expensive, and it definitely isn't as good, resolution wise, as a 50mm + FF. Bokeh is up in the air, it depends on a bunch of stuff, but with the money you save on the 50mm, and the inherent resolution improvement of FF, you could trade off some extra money and only 1.4x better resolution (instead of 1.5x) in order to improve bokeh.

The bottom line is that you can buy excellent lenses on FF. You can buy great lenses on APS-C, too. Other manufacturers don't make a lot of fantastic lenses in APS-C only because it doesn't make a ton of sense to the customer to be required to purchase only the best glass in order to have good performance on APS-C... the customers realize that after a certain threshold of IQ, it's better to go FF.

Keep in mind, too, that above "X" mm, it's tough to distinguish between an APS-C lens and a FF lens. Most of Pentax's lenses, above 50mm, heck, above 35 mm, do a pretty good job on FF. If Pentax's registration distance was shorter, or lenses used more of the clearance, it wouldn't be true.
07-04-2012, 02:46 PM   #143
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Got it, thanks a lot.

I had a chance to work with a 85L and a 5D last week and while it was definitely bulky to work with, I was really amazed at the 85L's IQ and rendering, and the amazing AF. Blows the K5+FA77 combo out of the water.

It really was the first time I envied Canikon for me. If people ask "Why Full Frame", that kind of combo would be a very good reason.

07-04-2012, 03:41 PM   #144
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Hopefully the K1 and 77 or DFA100 combo will be more on par (and less bulky!)
07-04-2012, 05:02 PM   #145
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Perhaps it will be more on par, but I doubt even a K1+FA77 would match say a D800+85G. Sure, it's a lot more money, but if you do have it, you have the option. The FA31, FA43 and FA77 are possibly the best glass Pentax has to offer, but they can't complete with Canikon's high end glass. In my opinion anyway. I love, love my FA77, but even I have to admit the 85L (I assume it's true for the 85G on a FF Nikon as well) has that extra ommph.

But I don't have the 5 grands I would need to make the switch, and business doesn't ask for it yet. So I'm staying put.

There certainly is something to envy on the other side, though
07-04-2012, 05:37 PM   #146
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Just resolution-wise, it'd likely be a wash. They both have pretty nice bokeh but it'd be tough to beat the Nikon, i'd want to see them tested head to head before I would give a preference.

IMO the biggest weakness is the purple fringing. To me it was unacceptable, and I wasn't really doing anything altogether unusual... and I'm color blind! Other people don't have problems so YMMV.

I wish Pentax would re-vamp it, and all the FA Limiteds, for quick shift and digital coatings.
07-04-2012, 06:25 PM   #147
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I'm going to insert my own summary, just for my own sake (so that I have all these ideas wrapped up decently in my head).

There are lots of options out there. There are lots of needs out there. No single option will be the best choice for everyone. Because there are so many options out there that each have their own technical merits, is exceedingly difficult to summarize the strengths and weaknesses of any one toolkit.

Photographic imaging equipment these days is phenomenally good. The baby's-toe sized cameras in simple phones have capabilities that some professional photographers a century ago would have mortgaged their homes to obtain. High-end cameras can do quite a bit more than phone cameras. Looking at them in their historical context is simply breathtaking. The camera I own--even the equipment it replaced--is more than capable of matching my own artistic ability.

Photography is a technical craft. Modern photography has lots of automation available which makes capturing images as simple as pushing a button. Still, when the photographer understands what their equipment is automating, they can gain ability to sometimes more reliably capture the images that they're attempting to record. If I want to be a better photographer, I should learn more about what my equipment is doing and practice using that knowledge.

(There's nothing wrong with being a photographer who doesn't know what's going on inside that black box the shutter is depressed. If this photographic process produces results that make you happy, then I have no standing to criticize you. Realize, though, that internet forums attract people with opinions they want to share. Like me.)

Asking a technical question is good; expecting easy answers is unrealistic. (This comment isn't directed to VoiceOfReason, but is a reaction to some of the tones I've seen taken in this thread.) While sharing opinions in response to a question on a forum such as this, it is a good practice to determine whether someone is asking for technical knowledge or qualitative opinion. For example:
Technical knowledge: Camera systems with a 135-frame sensor are available with 84 degree angle of view lenses that open to an aperture 8.5mm wide, as with a 24mm f/2.8; a Micro4/3 system can give you the same angle of view, or the same aperture, but not both in the same lens, which would be a 12mm f/1.4.
Qualitative opinion: While the 135-frame sensor system has more technical abilities, I would suggest considering making the small sacrifice of accepting a 12mm f/2 lens for the large benefit of lower weight, smaller size, and probably lower cost.
Either way, the writer is asking the reader to interpret the information, and the writer of technical information is asking a whole lot more of the average reader than the writer of qualitative opinion. One of the great things about this forum in particular is how much technical knowledge is shared here, and how patient this forum is in general with teaching people who come here with little more than enthusiasm.

In the end, the question "what are the advantages of full frame" is something that each person must answer for themselves, because "advantage" is something that applies to each person's situation. The best answer, perhaps, to this question would be:
-"What kind of limitations do you find with your current camera system? Only when we know what limits you're up against can we help you find ways around them."
Perhaps "what makes 135-frame camera systems different from APS-C camera systems" would be an easier question to address. My answer would simply be:
-"Larger sensors have more light-collecting space. This allows for equivalent images with lenses that have poorer design or manufacturing, but requires those lenses to take up more space; alternatively, it allows for lenses that would be prohibitively expensive to manufacture for smaller sensor formats. At some point, it becomes more expensive to obtain lenses for a smaller sensor than it costs to use a larger sensor with larger lenses. Of course, this does not mean that there is any particular sensor size or lens specification that is required to produce compelling photographs. If you don't have a compelling reason to buy the more expensive option, then you probably shouldn't choose it. In many ways, I wish I found the camera in my phone to be photographically satisfying, and I would be happy to hear that what you already have fully meets your needs."
07-05-2012, 03:52 AM   #148
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QuoteOriginally posted by ElJamoquio Quote
Just resolution-wise, it'd likely be a wash. They both have pretty nice bokeh but it'd be tough to beat the Nikon, i'd want to see them tested head to head before I would give a preference.

IMO the biggest weakness is the purple fringing. To me it was unacceptable, and I wasn't really doing anything altogether unusual... and I'm color blind! Other people don't have problems so YMMV.

I wish Pentax would re-vamp it, and all the FA Limiteds, for quick shift and digital coatings.
I wonder if the fringing is an aspect of the optical design, rather than a 'digital coating' thing? I'm a bit suspicious of anything with 'digital' prefixed to it, as so many pre-digital lenses do just fine and Pentax always used great coatings. Maybe few of the FA77s 'quirks' are due to designing a lens that size, and the designer's preferences in terms of the lens's 'character'.

Of course optical aberrations would also be diminished by using a larger sensor!
07-10-2012, 04:23 PM   #149
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QuoteOriginally posted by ElJamoquio Quote

If instead, you want a FF lens to 'exactly' match the APS-C + 31mm f/1.8, you'd design a 50mm f/2.8. .
Such a 50mm lens does't exist. They will not display the same minimum DOF or the same DOF range or the same close focusing distance or the same magnification at that distance. They will not give the same exposure at the same DOF either. They simply do not exactly match. Making DOF wide open as a benchmark for comparing lenses is meaningless; you could just as well use any of the above parameters (and they would have been more relevant for most). A 50/1.8 is equivalent to a 31/1.8. They will not display the same DOF but then different formats doesn't. They will give the same exposure wide open.
And why not turn the argument on its head? Where is the FF equivalent of the FA* 200/4 Macro used on APS? And what do you think it would cost? Would it be possible at all?
And where is the FF 24mm lens with 0.18m close focusing distance and a minimum aperture of F:32 (in order to "exactly match")?

Last edited by Pål Jensen; 07-10-2012 at 05:14 PM.
07-10-2012, 04:32 PM   #150
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QuoteOriginally posted by FrancisK7 Quote
Not trolling or arguing, I'm really just trying to wrap my head about the price discrepancy between Canikon's top glass (like the 85L, or Nikon's 24-70) versus Pentax's top glass, especially considering Canikon's top glass is marketed at professionals who most likely shoot FF.

You have reasons to be baffled. The math is really very simple; the bigger sensor the bigger lenses and bigger cost all things equal. This is the rule of thumb. There are always exceptions; eg you could argue that MF lenses are smaller and cheaper than K-mount lenses from the FA645 75/2.8.
If you do anything to make a small and larger format appear equal, in spite of the fact that they aren't and people buy them because they aren't, the larger format will win. This may be a funny game intelectually but it doesn't tell anything but the obvious. It may be true that FF is the most cost effective way to maximise image quality but most peoples choice is about meeting their needs, preferences and their budget.

Last edited by Pål Jensen; 07-10-2012 at 05:39 PM.
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