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04-06-2014, 03:02 PM   #76
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QuoteOriginally posted by dosdan Quote
I wonder if this is the case.
For the image centre -- using proper comparison criteria -- FF definitely provides better IQ.

You may want to consult falconeye's article "The true reasons for a full frame camera" article.

QuoteOriginally posted by dosdan Quote
Vignetting is usually present in most lenses used on a FF.
But not to the extent as people commonly believe.

In falconeye's words (see section "4.2.2. Corner performance" of "Camera Equivalence"):
"It is a myth that APS-C cameras "crop the sweet spot" of the image field of lenses which cover a larger image circle or are made for a full registration distance."


04-06-2014, 05:25 PM   #77
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QuoteOriginally posted by Class A Quote
If you are not yet using the widest possible aperture on APS-C that still provides you with an IQ that you are happy with, don't think that moving to FF will buy you a low-light/noise advantage.
Sorry, but I disagree. You have pointed out some variances on the settings and results used for the photos, but I did make it clear it's like comparing apples and oranges. Could I have shown calculations for each of the aspects you have pointed out? Perhaps, but that missed the point.

Whether I need to buy a "33/0.9" to get the same performance as a 50/1.4 on FF, or Nikon inflates their ISO settings to appear better than they are, or there is more crop on the Pentax photo.....it is irrelevant.

I can correctly point out that I get much better low light performance for the photos I take......full stop. I consistently get much cleaner photos and more "keepers" with this camera in low light.

Anyways, I hope Pentax releases something similar (APS-C or FF) so I can standardize on one set of lenses again.

Last edited by SteveM; 04-06-2014 at 05:47 PM.
04-06-2014, 06:05 PM   #78
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QuoteOriginally posted by SteveM Quote
I can correctly point out that I get much better low light performance for the photos I take......full stop.
You can do that, but -- sorry to be blunt -- that's like the guy that claims that a Nikon camera is better for sports than a Pentax camera based on his blur analysis.

You get better low light performance because you are using different settings that are better suited for low-light photography. They may not look like different settings because the numbers are the same, but they are different settings nevertheless.
04-06-2014, 06:38 PM   #79
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QuoteOriginally posted by Class A Quote
You can do that, but -- sorry to be blunt -- that's like the guy that claims that a Nikon camera is better for sports than a Pentax camera based on his blur analysis.

You get better low light performance because you are using different settings that are better suited for low-light photography. They may not look like different settings because the numbers are the same, but they are different settings nevertheless.
Sorry, but that would imply that I could just change my settings on the K3 for the same results, and that is incorrect.

Ironically, I have pointed out many areas where I think Pentax trumps the Df, and have only identified one area that I get better results. I still love my K5 for low light, and am not implying that you can't get terrific results from it and that another camera should be used instead.......but I also never felt the need to argue it as "the best" at all aspects of digital photography.

04-06-2014, 06:57 PM   #80
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QuoteOriginally posted by SteveM Quote
...but I also never felt the need to argue it as "the best" at all aspects of digital photography.
Neither do I.

This is not about Pentax vs Nikon, AFAIC.

QuoteOriginally posted by SteveM Quote
Sorry, but that would imply that I could just change my settings on the K3 for the same results, and that is incorrect.
First, you could change some settings to get better results.

a) Aperture: For the first two images, you use f/2.8 for the K-3 and f/2.2 for the Df. This disadvantages the K-3. Why not use f/1.8 for the K-3?

b) Shutter Speed: For your first two images, you are choosing the same manufacturer ISO value, but you get 1/80 for the K-3 and 1/60 for the Df. This disadvantages the K-3. You could just lower the ISO value of the K-3. This will imply a longer shutter speed and hence less noise. Even though the ISO value would look lower than the one you are using for the Df, the true ISO values used by the two cameras respectively would be closer then they are now.

Second, we disagree what "same results" mean. Unlike you, I maintain that you cannot compare 100% crops of cameras that have different amounts of MP. If you upscaled the Df images so that they show the same amount of magnification as the K-3 images show, you'd see more noise as well. Alternatively, you could downscale the K-3 images to 16MP which would decrease the noise.

Summarising, you did not optimise the K-3 settings for low-light yet and hence should not have any reason to use better settings for the Df (however, you do). Moreover, to see whether you can get the same results, you cannot use different benchmarks (e.g., 16MP vs 24MP magnification).

Last edited by Class A; 04-06-2014 at 07:08 PM.
04-06-2014, 07:15 PM   #81
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QuoteOriginally posted by Class A Quote
Neither do I.

This is not about Pentax vs Nikon, AFAIC.


First, you could change some settings to get better results. For instance, you could shoot the FA 77/1.8 at f/1.8 instead of f/2.5. You could also lower the ISO value of the K-3. This will imply a longer shutter speed and hence less noise. Even though the ISO value would look lower than the one you are using for the Df, the true ISO values used by the two cameras respectively would be closer then they are now.

Second, we disagree what "same results" mean. Unlike you, I maintain that you cannot compare 100% crops of cameras that have a different amount of MP. If you upscaled the Df images so that they show the same amount of magnification as the K-3 images show, you'd see more noise as well. Alternatively, you could downscale the K-3 images to 16MP which would decrease the noise.

Summarising, you did not optimise the K-3 settings for low-light yet and hence should not have any reason to use better settings for the Df (however, you do). Moreover, to see whether you can get the same results, you cannot use different benchmarks (e.g., 16MP vs 24MP magnification).
I've already said that I could have added comments to the shots to summarize your points and indicate why there is more noise with the Pentax shots, but at the end of the day, I can get a cleaner low light shots with the Df than with the K5 or K3. Just to be clear, the delta between these cameras is not a small one when it comes to low light and noise.

I do not believe you can consistently get the same results with the K3 by changing settings, changing the crop, etc..

We can go around and around and around back and forth, but we will continue to have different viewpoints on this, so I am going to leave it at that.
04-07-2014, 09:37 AM   #82
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QuoteOriginally posted by SteveM Quote
Just to be clear, the delta between these cameras is not a small one when it comes to low light and noise.
The delta is not between the cameras.

The delta is between lenses (and settings, in your case).

QuoteOriginally posted by SteveM Quote
I do not believe you can consistently get the same results with the K3 by changing settings, changing the crop, etc..
Of course an FF camera, in combination with faster lenses, can take images you cannot take with a K-3. But you will have to pay with less DOF for less noise.

I'm happy for anyone like you who is enjoying their new gear.

What I have a gripe with is are apples to oranges comparisons that start out with a disclaimer that they are "not scientific" and "apples and oranges" comparisons, but then proceed to compare nevertheless.

Let me explain what "apples to oranges comparison" means to me:

It is not a comparison where you state that, say "oranges are more orange than apples", i.e., point out a true difference between things that are actually different.

It is a comparison made based on criteria that are ill-fitted, such as determining that apples are a cheaper source of vitamin C than oranges, because apples are just 25 pence a piece whereas oranges are 50 pence a piece (ignoring the fact that one orange contains ten times the amount of vitamin C compared to an apple). Prices are made up in this example, but you get the idea.

What you did is akin to a jumping competition between Tom and Jerry, observing that Tom jumps 1m high and Jerry jumps 2m high, ignoring the fact that Jerry starts from a chair that is 1.5m high. Who is the better jumper? In actual fact, Jerry only jumps 1/2m but you are still claiming that Jerry is the better jumper on the basis that he reaches 2m compared to the 1m Tom manages.

Jerry can actually jump 3m by using special jumping boots which
a) Tom cannot wear, but
b) come at a price (less DOF).

So I'm not denying that your Df plus certain lenses can be better in low-light, but I'm saying the way you tried to demonstrate that was not a suitable one and misleading one.
04-07-2014, 11:44 AM - 1 Like   #83
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It's not often you need a *precise* DOF

QuoteOriginally posted by Class A Quote
My assumption is that a photographer wants to make a certain image with a certain DOF. That's why Av mode is very popular. If you know what DOF you would like, you simply choose the f-ratio accordingly.
In my experience, this ^^ isn't the case. That is, they are almost never looking for a precise DOF, they are looking for and are willing to accept a certain range of DOF, as long as their subject is not compromised.

I think that what matters to most people is, in order: 1) framing (FOV), 2) shutter speed (because motion blur or handshake ruins things beyond repair,) and then 3) noise or DOF. In low-light situations, noise is going to probably be #3 - in well-lit situations, DOF may be.

And here's the thing about #3 - 'too thin DOF' rarely ruins a non-landscape shot or non-macro shot - you have to be shooting close-in portraiture, or some group shots from fairly close-in to have to worry about stopping down because you're not going to get enough of your subject in acceptable focus.

Everyone can think of a case where they had 'too thin DOF' and needed to stop down, but if you look at the % of times that actually happens to you - it's rare. You can accept the DOF range you get more often than not - much more often than not. This makes the delta between what you get for the same F stop and FOV on aps-c and FF a non-issue, and you can enjoy the noise advantage. It's what SteveM is ultimately describing, and think this is exactly what DXOmark thinks as well, which is why they represent things the way they do.

In other words, if someone's buying a FF camera to shoot low-light, their shooting situations are most often within similar parameters to:



That's the 85 1.8D wide-open - more than enough DOF for what I wanted, and I could take advantage of the F-stop and resulting linear aperture to give me an almost completely noise-free ISO 3600 shot, while maintaining enough shutter speed to stop a moving toddler (1/125s). DOF was 'accepted' (and IMO, is nice.)

.


Last edited by jsherman999; 04-07-2014 at 11:56 AM.
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