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10-13-2021, 08:42 AM   #151
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TBH, I've been trying to follow this thread, but having trouble understanding some of the notions.

I think that a rough, simple rule-of-thumb is that the full frame format offers about a one-stop 'advantage' over APS-C in terms of imaging and print quality. However, it gets complicated when considering, say, ten-year-old FF implementations to modern APS-C cameras. I shoot with Pentax APS-C cameras, and do not have a full-frame model.

There have been a number of these "FF vs APS-C" threads over the years. Some have provided useful insights, others rehashed the same stuff, while at least one long thread degenerated and was 'closed' by moderators.

Here's an interesting article from 2013: How & Why Sensor Size Affects Image Quality (APS-C vs FF vs compact) - PentaxForums.com

- Craig


Last edited by c.a.m; 10-13-2021 at 05:47 PM.
10-13-2021, 11:09 AM   #152
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QuoteOriginally posted by Hidrieus Quote
I used to think that way too. That I could use for instance a 35mm f/1.8 lens in 16x24 sensor and have the same sense as if I was using a 52.5mm f/1.8 in 24x36 sensor. And using a 24mm f/1.8 lens in 16x24 would give the same sense as if using a 36mm f/1.8 lens in 24x36 sensor. Everybody wrote that just apply the 1.5 factor and choose wider lenses on your 16x24 camera to achieve near as possible the sense that a 24x36 sensor would give. The manuals of APS-C cameras say the same: just apply the 1.5 factor to focal length of lenses to understand the feeling of the 24x36 camera. But this is not the case. The 1.5 factor must be applied to the aperture also. I can not feel roughly the look of a 50mm f/1.8 in a 24x36 using a 35mm f/1.8 in a 16x24. I would need a 35mm f/1.2 which I think does not exist. Consequently I can not feel roughly the look of a 35mm f/1.8 in a 24x36 using a 24mm f/1.8 in a 16x24. I would need a 24mm f/1.2 which I am almost certain does not exist. The widest in 24mm is f/2.8 if I am not mistaken.
In an old post about the relation between the formats someone gave a useful article about the equivalence. I think it clears everything. I give the link:
Equivalence
True, but I never photograph wider than around 5.6 so I don't concern myself too much with aperture equivalency. Its all in how ya shoot, I guess. Preferences and all that. I just like the field of view, and never caring to use wide open apertures, dont really think about the equivalency at all
10-13-2021, 12:52 PM   #153
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QuoteOriginally posted by GUB Quote
I can't think of a setup to use that is as "apples to apples " as this one. He has been creative to arrive at it.
His lens and presumably it's aperture is common between the tests.
His subject magnification is matching (that is why the K5 has to be further away)
His pixel count is matching
Leaving the only variable the format size .
While you think that's the only variable you'd be wrong

Interesting experiment but doesn't actually show you much.
10-13-2021, 01:13 PM - 1 Like   #154
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QuoteOriginally posted by Dartmoor Dave Quote
Well, this "more information" stuff does seem like an overly complicated way of talking about what are really some very simple and well understood principles of photography.
Back in the film days myself and others around me attributed this principle simply to the fact the smaller negative has to be enlarged more.
Now in the digital age people take this and presume that if you increase the pixel density in the apsc until the apsc has the same pixel count as the FF (so the sensor resolution is matching) then that difference will disappear.

That is not the case and that is what I am trying to present.

10-13-2021, 01:20 PM   #155
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QuoteOriginally posted by ZombieArmy Quote
While you think that's the only variable you'd be wrong
So what other variable do you think is affecting the very clear outcome in this test?
10-13-2021, 01:28 PM   #156
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QuoteOriginally posted by GUB Quote
So what other variable do you think is affecting the very clear outcome in this test?
Just to name a few:

Human error (experiment should be repeated, ideally with other setups as well)

Atmospheric conditions at a distance (if shot outside)

Quality of the lens at close focus vs distant focus

The effect of an AA filter when cropping on higher pixel density sensors

Differences in the sensors themselves and their technology (CCD vs CMOS).

Not saying they're all gonna affect the end result but there are questions that need further investigation.
10-13-2021, 01:35 PM   #157
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QuoteOriginally posted by ZombieArmy Quote
Human error (experiment should be repeated, ideally with other setups as well)
I have a plan - may take a few days.

10-13-2021, 02:06 PM - 1 Like   #158
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I did read this through. It does look like a big number is being made out of obvious. Yes. FF has edge over aps-c.

The thing is that especially with K-3III that difference is being made smaller with DR and ISO performance as well as with resolution 26 - 36mp

But K-3III has very much better FPS(if that is important) as well as amazingly better AF than K-1. If that does make difference to you. I did just come back from event(paid) and I did not take k-1 with me even if it would have been better in couple situations, like where shallow Dof and/or higher MP and FF look would have been needed. If your shots are not in focus, it does have little to none meaning in your final image compared to aps-c image with less information, but all in right place.

That is the thing what one should think of, then again, in many cases these things don’t matter so much, depending on what you are shooting.

I do also have 24 mp FF(not Pentax, obviously) with kit lens. Compared to K-3III. Only noticeable thing is Dof, FF -look and a smidge better DR. ISO performance is much better with K-3III. No surprises there. I’m using it for video purposes and this is where it dominates. Not with images. OVF is very nice with K-3III. I can shoot all day, not the case with EVF… but that is completely different discussion.

Yes, Dof and FoV does look different on aps-c and FF. is it ‘that’ much that it does make a real difference. That is more important than other technical things(unless you pixel peep, or really want to have big image in front of you/your client/aunt). That said, I have both. For now, I do choose K-3III over other options I have…oh, and using lens like DFA*70-200 with it is very nice combo, sharp, lovely Dof great tones. Hard to tell difference from K-1 in real life shooting

Edit: K-3III DR is amazing. Compared to Panasonic S5, 24 MP FF sensor. It does amazingly well. Shadow & highlight recovery is way better. ISO noise is well handled as well as lack of hotpixels(better than K-1 in that regard too .. something to think about

Last edited by repaap; 10-14-2021 at 01:45 AM.
10-13-2021, 05:24 PM   #159
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QuoteOriginally posted by ZombieArmy Quote
Interesting experiment but doesn't actually show you much.
I agree.

---------- Post added 10-13-21 at 05:56 PM ----------

QuoteOriginally posted by GUB Quote
So what other variable do you think is affecting the very clear outcome in this test?
Her reply, and mainly that test does not reflect the reality of usage. These cameras are tools for taking photos. Who is going to shoot their K-5 in ordinary practice as is shown in this test? A K-5 in the course of general use will definitely be capable of superior results over the 6mp model. I have shot with both extensively. If there were no advancement, why did anyone purchase a K-5 after having had a K100D Super? Or the K10D or K20D? We know the MP race has diminishing returns as to improvement, but improvements are there. If images are needed to be downsized for internet sharing, then get the tool designed for that purpose- a smart phone. I do very little of this kind of thing, so I don't have one. If needed, I occasionally email a photo or two, but usually as large files.

I also do not buy the claim about a newer zoom lens delivering superior sharpness to any film-era prime lens because it is of newer technology. I'm on board with the DFA 28-105mm being better than any of the FA 28-105 zoom lenses, which is no surprise. The DFA 28-105mm is a very fine all-around zoom lens, not too weighty and having WR construction, and a real bargain for what you get. I have one and value it highly on my K-1 II. However, the FA HD 35mm f/2 and FA HD 31mm f/1.8 Ltd, for example, are still top-flight performers, not to mention their large apertures and compactness. Many other older prime lenses are very highly rated as well. As to older zoom lenses, I am getting great results with my oldie but goodie Tokina 28-70mm f/2.6-2.8 ATX PRO II on my K-1 II.

And also, the FOV and large aperture with similar performance of the FA 35mm f/2 and FA 31mm f/1.8 Ltd on the K-1 II, cannot be duplicated so far on APS-C.

Last edited by mikesbike; 10-13-2021 at 06:13 PM.
10-14-2021, 12:38 AM   #160
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QuoteOriginally posted by GUB Quote
Back in the film days myself and others around me attributed this principle simply to the fact the smaller negative has to be enlarged more.
Now in the digital age people take this and presume that if you increase the pixel density in the apsc until the apsc has the same pixel count as the FF (so the sensor resolution is matching) then that difference will disappear.

That is not the case and that is what I am trying to present.

Surely most people in the digital age understand that an APS-C with the same number of megapixels as an FF has much smaller individual pixels, so that a lens that's able to resolve the maximum possible detail onto the bigger pixels in the FF might not have enough resolution for the smaller pixels in the APS-C?
10-14-2021, 12:48 AM   #161
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QuoteOriginally posted by GUB Quote
So what other variable do you think is affecting the very clear outcome in this test?

It seems to me that the most important variable in that test is the size of the photoreceptors in the two different cameras. The DS has a CCD sensor, in which the entire surface area of each pixel is taken up by the photoreceptor. The K5 has a CMOS sensor, in which a significant part of each pixel area on the sensor is taken up by the readout transistors -- the photoreceptor itself only occupies part of the area (I'm assuming the K5 doesn't have a back side illuminated sensor).

So in those examples the photoreceptors in the DS are relatively MUCH bigger than the the ones in the K5. A 6 megapixel crop from a K5 will be MUCH more revealing about the lens resolution, much more revealing of any diffraction effects, and much more revealing of any focusing error. And that's caused by the smaller photoreceptors rather than the different overall surface area.
10-14-2021, 12:57 AM   #162
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QuoteOriginally posted by Dartmoor Dave Quote
Surely most people in the digital age understand that an APS-C with the same number of megapixels as an FF has much smaller individual pixels, so that a lens that's able to resolve the maximum possible detail onto the bigger pixels in the FF might not have enough resolution for the smaller pixels in the APS-C?
Well I word it as Format size rather than Pixel size (which when the pixel count is the same is the same thing) and I have copped a headwind here from a few.
Some seem to think the increased pixel density of the smaller pixels somehow offsets things.
10-14-2021, 01:11 AM   #163
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QuoteOriginally posted by Dartmoor Dave Quote
It seems to me that the most important variable in that test is the size of the photoreceptors in the two different cameras. The DS has a CCD sensor, in which the entire surface area of each pixel is taken up by the photoreceptor. The K5 has a CMOS sensor, in which a significant part of each pixel area on the sensor is taken up by the readout transistors -- the photoreceptor itself only occupies part of the area (I'm assuming the K5 doesn't have a back side illuminated sensor).

So in those examples the photoreceptors in the DS are relatively MUCH bigger than the the ones in the K5. A 6 megapixel crop from a K5 will be MUCH more revealing about the lens resolution, much more revealing of any diffraction effects, and much more revealing of any focusing error. And that's caused by the smaller photoreceptors rather than the different overall surface area.
So if I was to do a comparison between the K01 and the K1 and set the jpg output of the K1 to "S" (12mp) and potentially the K01 to "M" (also 12mp) would the original pixel counts muck things up?
10-14-2021, 07:27 AM   #164
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QuoteOriginally posted by beholder3 Quote
Oh, boy.

Even the - mostly irrelevant - measurements-wise "better" discussion is not possible without massive subjective bias.

We are talking about zoom lenses. If the person making the decision has a subjective preference for the shorter focal lengths then story might be quite different from looking at the long ends (where the DFA24-70 is weakest).
Then we have the subjective question which aperture values are most relevant in actual use.
And we have the third question about how relevant extreme corner sharpness is.

Picking out 1) 45mm APSC equivalent + 2) F2.8 absolute + 3) extreme corners is a triple subjective decision that will lead to a fully subjective "better" based on measurements.
And it is highly possible that the APSC combo will win hands down.

Now one could as well include more "techno image quality " relevant aspects like 4) vignetting (which is a nice way of discussing noise on edges) where APSC usually is quite superior.
Or look at 5) lateral CAs where APSC image quality also tends to be better.
Are these aspects relevant for the decision maker?

So we have at least 5 completely subjective factors upon which the "better" discussion hinges.
Absolutely. But don't confuse a subjective decision with an objective measurement, even an eyeball one that isn't quantified.
10-14-2021, 08:31 AM - 1 Like   #165
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QuoteOriginally posted by GUB Quote
So if I was to do a comparison between the K01 and the K1 and set the jpg output of the K1 to "S" (12mp) and potentially the K01 to "M" (also 12mp) would the original pixel counts muck things up?

The downsampling would make it invalid as a test of. . . whatever it is you're actually trying to test. I'm a bit befuddled by it all at this point, because as far as I can tell there's nothing going on in this thread that doesn't involve simple principles of photography that have been well understood for almost 200 years.

I really hate being in any sort of disagreement with you, because you're a member whose opinions and knowledge I highly respect, so I think reluctantly I'm going to have to bow out of the thread now. Otherwise I think we'll end up just going "Oh, no it isn't!" and "Oh, yes it is!" at each other.
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