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11-04-2018, 10:18 PM   #166
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QuoteOriginally posted by pschlute Quote
I don't get this. How can cropping an image change the amount of light that the subject was recorded with ?
The same way using a smaller sensor , which is no different than cropping will reduce the amount of light that will be found in the image

---------- Post added 11-04-2018 at 11:33 PM ----------

QuoteOriginally posted by pschlute Quote
This will largely depend on what you want to do with your image. If you want to print large then you have a point. But if you are mainly using your image for online viewing then a 6mp crop should provide excellent detail. I use a 2560x1440 resolution monitor, only need 3.7 mp crop/resampled images to display them in fantastic detail.
How we view images has changed with the advent in the digital age, the way I now look at images is as a interactive format rather than a final print with a set print size. More or less how we used slides in the past but with the ability to pick and choose how we view the image in an interactive way.

There is also the problem of the unwanted artifacts that will plague the image when cropping too much like noise, less DR, false detail, NR, lens faults, focus error and loss of contrast. Too often times the any use to correct these artifacts will in themselves create more issues


Last edited by Ian Stuart Forsyth; 11-04-2018 at 10:39 PM.
11-06-2018, 11:11 AM - 1 Like   #167
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I've just bought a new (old stock) K-1 but my path has seen a few distractions, I still shoot film bodies so I always shot 'FF' in that respect. When Ricoh bought Pentax (which was a big confidence boost) and rumours of the K-1's imminent arrival re-surfaced, I bought some used FA lenses - I needed aperture rings for my film bodies and FA lenses seemed the way to go. Then the K-1 stalled and I bought a P6x7, the K-1 then arrived but I was having too much fun with 6x7 film. Then UK K-1 prices soared as a result of currency fluctuations to about £2k and therefore no longer justifiable - they started dropping just when the K-1ii arrived but very quickly sold out (the K-1ii was basically back to £2k at this point). Recently some more K-1s have become available at a reasonable price and I've snapped one up (buying a new from a dealer with full warranty is much better bet than a used one with little backup).

I still have my K-5 and a couple of DA lenses - I've still to decide what to do with these - I can't see me wanting to use crop lenses (or crop mode) on the K-1, but a spare body might come in useful. I'm happy to carry medium format kit about so my interpretation of 'small & light' may differ from others, but there may be occasions where they'd be handy.

So am I happy with FF? - Yes (the viewfinder & handling alone are worth it), I prefer the size of the K-1 and I have s decent selection of FA (and earlier) lenses to go at. I dislike the modern huge zooms (some look bigger & heavier than my P67 55-100!), my FA20-35 & FA43 are likely to be my most used lenses with probably a 135mm doing most of the rest. I don't shoot action and mostly use single shot, single point AF, so screw drive lenses aren't an issue.

For me it's more about a camera that's better to use** (better viewfinder, slightly larger & ergonomics) that brings my focal lengths back to where they should be rather than chasing ultimate IQ - I'm not suggesting it won't offer it, only that it's a longer learning curve* when I'd just rather be shooting.

* I need a better computer, my post processing (erm - 'process') could be better.

Edit: ** The only gripe I've found so far is the AF point illumination - I prefer the red outline illumination of the K-5 over the back box on the K-1 - still trying to work out if there's a setting for this...

John.

Last edited by johnha; 11-06-2018 at 11:16 AM. Reason: See text
11-06-2018, 12:06 PM   #168
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QuoteOriginally posted by photoptimist Quote
APS-C may excel at reach but every FF camera made contains an APS-C camera built right into it.
That would only be true for a K-5.
For those of us who wanted the resolution increase, k-5 to K-3, a K-1 in crop mode is a step back. 2100 lw/ph vs 2700.
The K-1 only gets you 3500 lw/ph another 800 over a K-3. If K-5 to K-3 isn't worth it, by the same measurement ratio, neither is K-3 to K-1. The only worthwhile jump would be the 1400 lw/ph jump from K-5 to K-1.

Ian, you've outdone yourself this time in terms of an obtuse impossible to understand post.
QuoteOriginally posted by Ian Stuart Forsyth Quote
One of the biggest hurdles I was facing when using pixel density to increase my reach was the light loss as the result of this reach through cropping. The resulting side effect of cropping was that I needed more light and I was left using the lens at its widest and/or shutter speeds not the best for the condition I was shooting in if I was concerned about noise.
So are you saying that instead of say ƒ5.6 you needed ƒ4 because you cropped? How did you measure this light loss? Maybe you could give us more detail about actual settings you think need to be changed shooting a 6 MP crop. I assume you are talking about a 6 MP crop taken out of the middle of a 24 MP image, which would have exactly the same DR, resolution, colour depth etc. as if it were still attached to the image it was cropped from. You simply need more light if there's more picture.

A 3000x2000 image displayed on my 2650 by 1600 monitor will look exactly the same as the same images taken with a 36 MP camera or a 24 MP camera.. The amount of light originally collected by the different sensors will make no difference. The fact that the image might have been cropped from a 7200 by 5000 sensor will make no difference. AN APS_c sensor to match the K-1, you do need more light intensity ƒ5.6 instead of ƒ8 to get the same depth of field so the smaller sensor while having not as good low light performance can be exposed at a wider ƒ stop.

Shooting in my blind, shooting the K-3 at ƒ5.6 uses the same amount of light to form the image as the K-1 at ƒ8 if speed and ISO are the same and with the DoF being the same you should have identical images.
Same amount of light used. Half the sensor size but double the light intensity of the K-1. I think we've been through this before.

An image taken with an extreme example the XG-1, a 1:1.2 sensor so very small. IN this case the small sensor at ƒ3 allows me to achieve much more DOF than would be possible in these relatively dark light conditions that I wouldn't be able to get with a larger sensor, where a large f-stop would mean very shallow DOF. The wide aperture on the small sensor allows me to both keep my shutter speed up, and maintain the necessary DoF. And using the wide aperture also increase the amount of light available to each pxiel to form the image. I took this camera out this day because it was too dark to get the same image with APS_c or FF without a tripod. So, I'm quite confused about what you are talking about. I'm pretty sure if you take the time to look at actual exposure settings from actual images you'll understand what I'm talking about.

The crop sensor advantage is, for the same amount of light intensity, you can maintain your depth of field while using a much faster ƒ-stop to increase your shutter speed. You can only shoot between 100 and 200 ISO but because you can open to ƒ2.8 maintaining your DoF, that's not really a disadvantage.

I'm guessing here at what you might be alluding to.

XG-1 @ ƒ3. To get the same depth of filled you'd need ƒ5.6 on APS_c or ƒ8 on FF. But you'd end up with the same image. Especially in this case because the image doesn't tax the dynamic range, which is one of the week links of the smaller sensor, but which is not needed in every image.


The crop sensor gives you enough DoF at ƒ2.8 to keep everything in focus on image like the above. There's absolutely no reason to stop down using less light.

For a similar image taken with a K-3 I used ƒ8 and still didn't have enough depth of field. The XG-1 uses 8 times as much light intensity on a sensor approx. 1/8 the size, using the amount of light on the smaller sensor. But shooting ƒ2.8 on the smaller seρor give you a two stop advantage in shutter speed. Which if I read you correctly is pretty much the exact opposite of what you said. However, you're so loose with your terminology, I can't actually tell what you mean.


I suspect what you meant was that if you cut a 6MP file out of a 24 MP image you lose 1/3 or the original resolution. So if you shot 24 MP file at approximately 2800 and cut id down to 6MP you'd lose 3/4 of your resolution meaning and have made 600 lw/ph. But the part about the light thing is confusing. But we all know pixel density increases in the smaller sensors so even that is misleading. The only thing it will cost you is high ISO performance, which is mitigated by the fact that you can shoot at wider apertures, and the Dynamic range of the deeper wells on the larger pixel sites, which is mitigated by the fact even a 10 EV DR camera can have enough DR to accurately portray low contrast subjects.

Last edited by normhead; 11-06-2018 at 12:32 PM.
11-06-2018, 02:58 PM - 2 Likes   #169
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QuoteOriginally posted by normhead Quote
That would only be true for a K-5.
For those of us who wanted the resolution increase, k-5 to K-3, a K-1 in crop mode is a step back. 2100 lw/ph vs 2700.
The K-1 only gets you 3500 lw/ph another 800 over a K-3. If K-5 to K-3 isn't worth it, by the same measurement ratio, neither is K-3 to K-1. The only worthwhile jump would be the 1400 lw/ph jump from K-5 to K-1.
Without exception, all FF cameras have an APS-C camera inside although it is true that the APS-C camera inside a given FF camera may not be the highest-resolution APS-C camera on the market. The K-1 contains a K-5. A 24 MPix FF camera would contain a K-10D in resolution. If Pentax ever makes a 54 Mpix FF camera, it will contain a K-3.

But I seem to recall a certain someone on these forums arguing repeatedly that most people don't really need super-high resolution for decent-sized prints or big-screen viewing. So maybe the free K-5 inside the K-1 is good enough.

11-06-2018, 03:44 PM   #170
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QuoteOriginally posted by Ian Stuart Forsyth Quote
The same way using a smaller sensor , which is no different than cropping will reduce the amount of light that will be found in the image
Absolutely not part one.
Start with a K-1 image.
A K-3 image is not the same as the K-1 crop.
My XG-1 image is not the same as a 1/8 crop of a K-1.
Pixel density changes.
A K-1 crop is 15 MP, a K-3 is 24 MP, and the XG-1 is 16 MP.
With different pixels densities you have different numbers of MPs in the area of the crop.

Absolutely not part two.
To compare images you must have the same DoF, or it's a different image and you can't compare.

Shoot an image with the K-1, you will have 1 units of light times 1 second. 8 units of light.
For the same DoF, the K-3 will be exposed at ƒ5.6/ You capture twice as much light due to the wider ƒ-stop, but you expose a sensor tha has half the surface area, so same total light.
Now the XG-1. To match the K-1 DOF I have to go all the way to ƒ2.8. 8 times the light intensity but 1/8the the surface area. Still the same amount of light to expose the frame.
All this with constant exposure times to keep it simple.

I have explained this to you so many times.... yet you keep repeating the easily discredited total light scenario by ignoring that you are comparing different photos. Photos with different DoF are different photos and cannot be used for this type of comparison. To make a comparison, the results must be roughly the same.

If you shoot the K-1, K-3 and XG-1 )1:1.2 crop)all at 20mm at ƒ2.8, you get very different images. The K-1 has less DoF than the APS-c. The K-3 has tremendously narrower DoF than the XG-1. The K-1 and K-3 images will be pretty similar, although some claim they have to have FF just for the 1 stop narrower DoF at the same aperture. But the XG-1 image won't look much like the other two. It's not the same image.

Why do you insist on comparing apples and oranges? ( Because it's a way to fudge the data?)
Why are you so committed to this completely erroneous notion?

This is rookie mistake material.

Last edited by normhead; 11-06-2018 at 04:10 PM.
11-07-2018, 02:01 AM   #171
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QuoteOriginally posted by normhead Quote
So are you saying that instead of say ƒ5.6 you needed ƒ4 because you cropped?
No what I am saying is that anytime you want to decrease the how much light that you can store within the final image, If you are cropping your 24mp image to a 6mp image the cost of doing so is how much light that you have access to and the ability to store within the limits of the sensor.
QuoteOriginally posted by normhead Quote
How did you measure this light loss? Maybe you could give us more detail about actual settings you think need to be changed shooting a 6 MP crop.
There are no setting if you select to crop the image your are inadvertently limiting how much light that image will be made from.

QuoteOriginally posted by normhead Quote
I assume you are talking about a 6 MP crop taken out of the middle of a 24 MP image, which would have exactly the same DR, resolution, colour depth etc. as if it were still attached to the image it was cropped from. You simply need more light if there's more picture.
You have cropped out the light the image sensor has captured, so the image will no longer have the same DR, color depth as you have cropped the signal that gives you those image quality's. As for cropping and resolution you loose resolution there also. Take the average lens on a 24mp sensor will give you 3600lw/ph if you are to crop that into a 6mp you are left with 1800lw/ph in the final 6mp image. You may have decreased the FOV but that comes at a cost and that is light and resolution.

QuoteOriginally posted by normhead Quote
The fact that the image might have been cropped from a 7200 by 5000 sensor will make no difference. AN APS_c sensor to match the K-1, you do need more light intensity ƒ5.6 instead of ƒ8 to get the same depth of field so the smaller sensor while having not as good low light performance can be exposed at a wider ƒ stop.
That only applies if you are shutter speed limited
QuoteOriginally posted by normhead Quote
Shooting in my blind, shooting the K-3 at ƒ5.6 uses the same amount of light to form the image as the K-1 at ƒ8 if speed and ISO are the same and with the DoF being the same you should have identical images.
Only if you are shutterspeed limited will you capture the same amount of light, and even this will not be the same as you can substitute the extra detail from the K1 for more of an aggressing NR, in real world uses you can shoot your k1 at a faster shutter speed and use the additional resolution to decrease the noise level with that NR.


QuoteOriginally posted by normhead Quote
An image taken with an extreme example the XG-1, a 1:1.2 sensor so very small. IN this case the small sensor at ƒ3 allows me to achieve much more DOF than would be possible in these relatively dark light conditions that I wouldn't be able to get with a larger sensor, where a large f-stop would mean very shallow DOF.
Nothing stops you from stopping down the FF to achieve the same DOF.

QuoteOriginally posted by normhead Quote
I took this camera out this day because it was too dark to get the same image with APS_c or FF without a tripod. So, I'm quite confused about what you are talking about. I'm pretty sure if you take the time to look at actual exposure settings from actual images you'll understand what I'm talking about.

The first part of this statement tell me that you should really think about " it was too dark to get the same image with APSc or FF without a tripod" all you would have to do it shoot the other formats with the same aperture dia and shutterspeed and you could have used ether FF or cropped.


And that a good point you made about taking a look at the actual exposures of an image, so let go back to cropping and light loss and provide evidence that there is light loss.

Take a person using FF and a 600mm lens and lets say they use iso100 F8.4 1/300 sec, now if you are the a person using a aspc 24mp camera and you only use a 6mp crop that that sensor to get you to the same FOV from a 200m lens. We know that to get the same amount of light and DOF as that FF shot you would only need to use that lens at f2.8 but there is no way that you would be able to shoot that image at the same shutter speed as you would over expose your image (more light).
Lets look a the exposures again more closely 600mm iso 100 f8.4 1/300sec vs 200mm iso 100 F2.8 but to keep the same level of image lightness you would need to use a shutter speed of 1/1250sec instead of the 1/300sec, if you are using a faster shutter speed then it means less light about 1/8

QuoteOriginally posted by normhead Quote
But the part about the light thing is confusing. But we all know pixel density increases in the smaller sensors so even that is misleading. The only thing it will cost you is high ISO performance, which is mitigated by the fact that you can shoot at wider apertures, and the Dynamic range of the deeper wells on the larger pixel sites,
It will also cost you how much light you can capture, this in turn limits your DR color depth and how clean your tonal ranges will be.


If it was only about high iso performance and shooting at wider fstops, you forget that how much light you can capture is limited to you by how much you can store before clipping.

There is no way you can use a 200mm on a 24mp apcs camera at iso 100 f8 1/300sec and hope to capture the same amount of light when using the same camera with a 100mm then cropping to 6mp to get the same FOV and the same DOF as the sensor cannot store the light the uncropped image gathered. Granted most cameras have more than enough DR to me its more about how much light I can make use of and any time you start to use a smaller image circle you limit the light you can store. This is most evident when shooting at base iso, we know this as anything that falls within the midtones is made up of 1/8 to 1/16 of the light the image sensor can store this becomes a problem.

---------- Post added 11-07-2018 at 03:05 AM ----------

QuoteOriginally posted by normhead Quote
A K-3 image is not the same as the K-1 crop.
My XG-1 image is not the same as a 1/8 crop of a K-1.
Pixel density changes.
A K-1 crop is 15 MP, a K-3 is 24 MP, and the XG-1 is 16 MP.
With different pixels densities you have different numbers of MPs in the area of the crop.
You may want to reread the post you quoted, If you crop you will lose light. If cropping does not reduce the amount of light the please tell me how would you capture the same amount of light with this FF camera shot at iso 100 f8 1/200sec ?

---------- Post added 11-07-2018 at 03:06 AM ----------

QuoteOriginally posted by normhead Quote
Absolutely not part two.
To compare images you must have the same DoF, or it's a different image and you can't compare.
Ok then use the same DOF as the above question I asked you already, use the same DOF and tell me how you would capture the same amount of light ?

---------- Post added 11-07-2018 at 03:40 AM ----------

QuoteOriginally posted by normhead Quote
For the same DoF, the K-3 will be exposed at ƒ5.6/ You capture twice as much light due to the wider ƒ-stop, but you expose a sensor tha has half the surface area, so same total light.
Now the XG-1. To match the K-1 DOF I have to go all the way to ƒ2.8. 8 times the light intensity but 1/8the the surface area. Still the same amount of light to expose the frame.
All this with constant exposure times to keep it simple.
At least 3/4 of my wildlife and landscape photograph does not require me to use the same exposure time.
QuoteOriginally posted by normhead Quote
I have explained this to you so many times.... yet you keep repeating the easily discredited total light scenario by ignoring that you are comparing different photos. Photos with different DoF are different photos and cannot be used for this type of comparison. To make a comparison, the results must be roughly the same.
If you have a surplus of light why would you sluff off much of the light you are given with more of a shutter speed than needed, while it is nice to use equivalence to compare cameras across different formats a great deal of the time you don't need to shoot equivalent to get the images in the real life.

Take this image here there was no need to shoot it at iso 200 as I could shoot it at a slow enough shutter speed even when I choose to expose it for raw



---------- Post added 11-07-2018 at 03:46 AM ----------

QuoteOriginally posted by normhead Quote
Why do you insist on comparing apples and oranges? ( Because it's a way to fudge the data?)
Why are you so committed to this completely erroneous notion?
This is rookie mistake material.
In real life you seldom need to shoot using an applies to applies comparison, a lot of the time we waste the light we are given with shutter speeds that are not need

K-1 or K-3 for birding - Page 2 - PentaxForums.com


You could call this a rookie mistake that I pointed out to you and all you did was insult me oh well
11-07-2018, 03:54 AM   #172
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QuoteOriginally posted by Ian Stuart Forsyth Quote
No what I am saying is that anytime you want to decrease the how much light that you can store within the final image, If you are cropping your 24mp image to a 6mp image the cost of doing so is how much light that you have access to and the ability to store within the limits of the sensor.

There are no setting if you select to crop the image your are inadvertently limiting how much light that image will be made from.



You have cropped out the light the image sensor has captured, so the image will no longer have the same DR, color depth as you have cropped the signal that gives you those image quality's. As for cropping and resolution you loose resolution there also. Take the average lens on a 24mp sensor will give you 3600lw/ph if you are to crop that into a 6mp you are left with 1800lw/ph in the final 6mp image. You may have decreased the FOV but that comes at a cost and that is light and resolution.



That only applies if you are shutter speed limited

Only if you are shutterspeed limited will you capture the same amount of light, and even this will not be the same as you can substitute the extra detail from the K1 for more of an aggressing NR, in real world uses you can shoot your k1 at a faster shutter speed and use the additional resolution to decrease the noise level with that NR.




Nothing stops you from stopping down the FF to achieve the same DOF.




The first part of this statement tell me that you should really think about " it was too dark to get the same image with APSc or FF without a tripod" all you would have to do it shoot the other formats with the same aperture dia and shutterspeed and you could have used ether FF or cropped.


And that a good point you made about taking a look at the actual exposures of an image, so let go back to cropping and light loss and provide evidence that there is light loss.

Take a person using FF and a 600mm lens and lets say they use iso100 F8.4 1/300 sec, now if you are the a person using a aspc 24mp camera and you only use a 6mp crop that that sensor to get you to the same FOV from a 200m lens. We know that to get the same amount of light and DOF as that FF shot you would only need to use that lens at f2.8 but there is no way that you would be able to shoot that image at the same shutter speed as you would over expose your image (more light).
Lets look a the exposures again more closely 600mm iso 100 f8.4 1/300sec vs 200mm iso 100 F2.8 but to keep the same level of image lightness you would need to use a shutter speed of 1/1250sec instead of the 1/300sec, if you are using a faster shutter speed then it means less light about 1/8



It will also cost you how much light you can capture, this in turn limits your DR color depth and how clean your tonal ranges will be.


If it was only about high iso performance and shooting at wider fstops, you forget that how much light you can capture is limited to you by how much you can store before clipping.

There is no way you can use a 200mm on a 24mp apcs camera at iso 100 f8 1/300sec and hope to capture the same amount of light when using the same camera with a 100mm then cropping to 6mp to get the same FOV and the same DOF as the sensor cannot store the light the uncropped image gathered. Granted most cameras have more than enough DR to me its more about how much light I can make use of and any time you start to use a smaller image circle you limit the light you can store. This is most evident when shooting at base iso, we know this as anything that falls within the midtones is made up of 1/8 to 1/16 of the light the image sensor can store this becomes a problem.

---------- Post added 11-07-2018 at 03:05 AM ----------



You may want to reread the post you quoted, If you crop you will lose light. If cropping does not reduce the amount of light the please tell me how would you capture the same amount of light with this FF camera shot at iso 100 f8 1/200sec ?

---------- Post added 11-07-2018 at 03:06 AM ----------



Ok then use the same DOF as the above question I asked you already, use the same DOF and tell me how you would capture the same amount of light ?

---------- Post added 11-07-2018 at 03:40 AM ----------



At least 3/4 of my wildlife and landscape photograph does not require me to use the same exposure time.

If you have a surplus of light why would you sluff off much of the light you are given with more of a shutter speed than needed, while it is nice to use equivalence to compare cameras across different formats a great deal of the time you don't need to shoot equivalent to get the images in the real life.

Take this image here there was no need to shoot it at iso 200 as I could shoot it at a slow enough shutter speed even when I choose to expose it for raw



---------- Post added 11-07-2018 at 03:46 AM ----------



In real life you seldom need to shoot using an applies to applies comparison, a lot of the time we waste the light we are given with shutter speeds that are not need

K-1 or K-3 for birding - Page 2 - PentaxForums.com


You could call this a rookie mistake that I pointed out to you and all you did was insult me oh well
It's funny that there is so much focus on wildlife/birding photography in this thread. I wouldn't have said that that was a strong point of full frame, although clearly you can do it. The question is really one of how close you can get to your subject and if you can fill the frame with minimal cropping. Obviously if you have to crop a full frame image past an APS-C crop, it will give no advantage over an APS-C image cropped to the same. That probably goes without saying.

There are plenty of situations, like portrait photography and landscape photography, where there is absolutely no problem in filling the frame and those are certainly areas where shooting a full frame camera can give benefit.

Part of the question is what happens when you print/view your final image. Shooting with a smaller sensor requires more magnification to get to the same display size. Unfortunately, this can lead to you noticing softness, noise, and lens flaws more than when using a larger sensor. The higher the pixel density the more you have to work to get an image pixel sharp. If someone came out with 50 megapixel APS-C camera, it would have a lot more "reach" over existing cameras, but it also would be really, really hard to get pixel sharp.
11-07-2018, 04:37 AM - 1 Like   #173
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I still don't follow this at all.

If I point my K1 at a subject and use spot meter to get the right exposure, it doesn't change when I switch to crop mode.

If I take the correctly exposed FF image and crop it in pp the subject does not change brightness.

If I use my incident light meter to take a reading it does not ask me what format I am using or what size I intend to crop to.

11-07-2018, 04:51 AM   #174
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QuoteOriginally posted by Rondec Quote
It's funny that there is so much focus on wildlife/birding photography in this thread. I wouldn't have said that that was a strong point of full frame,
It was a bigger deal when we only had 6, 10, 16mp with FF but as we start into the 24 and 36mp FF there is less of a dominance for wildlife and cropped bodies other than buffer and frame rate and cost but if I had to carry and use one body it would be FF.


QuoteOriginally posted by Rondec Quote
The higher the pixel density the more you have to work to get an image pixel sharp. If someone came out with 50 megapixel APS-C camera, it would have a lot more "reach" over existing cameras, but it also would be really, really hard to get pixel sharp.
You can already see this in 24mp cameras FF and cropped even when the FF 24mp camera has a AA filter it still with capture more resolution over a cropped camera without the filter. If we just look at the captured resolution between both 24mp cameras if we look at how much we can further crop based on captured resolution it only falls in around 1.35 crop factor and this is with a camera that employees a filter.

For me the narrow gap where a cropped 24mp camera excels at reach (iso 100-400) and in the area where diffraction really limits what you can see then what's the scene of the camera. As lenses start to fill out a lineup in the longer FL it's even less of a worry with reach . One of the arguments we see is an image showing a a K3 with 200 2.8 and a k1 and 300mm F2.8 well of coarse one setup will be heavier but if they went with the k1 and 300 F4 they are comparable in weight , DOF and FOV but one has a lot more reach over the other and all the benefits of FF. If we take a look at the reach factor between the K3 and K1 based on pixel density it falls within the 1.22 crop factor range, to put it into perspective at a working distance for small birds and a 500mm lens at 10m you would only have to setup your camera 1.5m closer for the FF camera.

---------- Post added 11-07-2018 at 06:04 AM ----------

QuoteOriginally posted by pschlute Quote
If I point my K1 at a subject and use spot meter to get the right exposure, it doesn't change when I switch to crop mode.

Your meter and exposure is based on a unit of area measurement so no it will be the same. The light that the larger sensor captured when cropped will not be used so there is less light going into the image.

QuoteOriginally posted by pschlute Quote
If I take the correctly exposed FF image and crop it in pp the subject does not change brightness.
As it shouldn't

QuoteOriginally posted by pschlute Quote
If I use my incident light meter to take a reading it does not ask me what format I am using or what size I intend to crop to.
A very simple test you can do to see the difference in the light that you can gather between using and the whole image is to do this little test

Take you k1 something like 300mm lens and shoot it using iso 100 F8 and the shutter speed the camera selects. Then set your camera to 1.5 crop and select iso 100 and use a lens that would give you the same FOV this would be 200mm but to keep the same DOF you will need to set the lens to F5.3 then notice to happens to your shutter speed and then see what happens if you force the camera to use the same shutter speed?
11-07-2018, 07:10 AM   #175
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QuoteOriginally posted by Ian Stuart Forsyth Quote
In real life you seldom need to shoot using an applies to applies comparison, a lot of the time we waste the light we are given with shutter speeds that are not need
And this is how this whole total light thing is perpetuated. By ignoring the fact that in real life different sensors are not the same as cropping the same image from a larger sensor. that the nature of the image is changed as you crop and expand to the same size.

It also ignores a number of other factors.

36 MP image reduced in size.


4 MP crop.


One was produced with a fraction of the light, but they look the same on my monitor. There is no reduction in light in the output. The output the light values are equal, and will be even if you were to print to 100 inches.

The important stuff.
Even though heavily cropped, there is exactly the same light intensity used on each pixel, there has to be, it's the same image.
If I were to enlarge the cropped image, the enlargement software would add pixels. It would add pixels which would I'n effect be the same as light added

Depth of Field (DoF) calculator | PhotoPills
Using this DoF guide.
FF sensor - Focal Length 300, ƒ8 2 meters DoF, 10meters. DoF .52 meters shutter speed 1/60s (actual measurement)
APS-s sensor 'Focal length 200mm, F5.6. 10 meters, DoF .55 meters. shutter speed 1/125s ((actual measurement)

The APS-c sensor uses Double the light for half the time. So the exposure is the same. The only place the FF has an advantage is in total surface area. More light gathering capacity. But in actual practice the reduction in size ou need to view an image means you throw away a lot of the light the APS_c image cpatured, and even more of that captured by the FF. You add pixels during enlargement to compensate for less total light. And in most instances like the one above, you are actually throwing away. If you take an APS_c image and crop to reduce the image size to 3650 x 2100 for your 4k TV, you throw away. 20 MP of your 4k image. To crop the FF 36 MP image you throw away 32 MP. So up to the size of the APS-c image you are actually wasteing the extra light you collected with the larger sensor and ir has no effect. So yes you used more light to form your image, but you don't use it in your output.

My images look fine on a 110 dpi computer screen but I'm sure 100 dpi would be the same. . So the 6000x 4000 24 MP image of my K-3 will lbe optimal up to 60 inches and probably well beyond, because upscaling software creates the effect of adding extra light you get with the larger sensor for you, while the software that down scales your image throws away light.

I have a 42 inch print on my wall, taken with a K-3. And it looks great. I suggest the only time the additional light surface used on the larger sensor would be for images over 60 inches. No one has ever established the point at which people will notice a difference between a large print printed with an FF and one printed with APS-c. ( I actually don't believe there is such a point and people have taken to comparing even 4/3 images to FF with no noticeable difference. And honestly when you look at the numbers, 6000 pixels wide compared to 7300 pixels wide, that's not surprising.

So there you have it. The theoretical, and the practical. My guess is if you aren't printing more than 60 inches wide there you are getting nothing for the extra light collected by the FF sensor. It's of no practical value. And its quite possible that even up to 100 inches wide, you get nothing of value.

So, you do use a lot more light to create an FF image, but there is no demonstrable value to the images because of that. Even on images with more dynamic range could be where more light creates more dynamic rangeused, it's not always the use of that dynamic range creates a more pleasing image. Negative space is a real thing. Black shadows with no detail can be appealing. Most of the time you throw it away a lot of the collected light downsizing an FF image. And even on over 60-100 inch prints it provides no demonstrable practical advantage. Especially if you look at the print from a practical viewing distance. You may be able to see increased detail, but no one has ever shown that, that level of increased detail makes viewing the print more enjoyable.

The total light collected is irrelevant to the enjoyment of images except in untested notions where at some unknown point of enlargement, probably imaginary, people might be able to notice a difference using a loupe. But it has never been shown that is relevant to people's enjoyment of the images. In digital a 4 MP file is a 4 MP file, and it doesn't matter how big the sensor was that created the original image or how many MP the original was for all but a small fraction of photographic practice.It's not the quantity of light you collect, it's the quality of that light. And in the digital world 4 MP file looks really good on a 55" 4k TV, while sitting in the lazy boy drinking beer. My preferred from of viewing.

When I got my K-1 I spent a pile of time trying to show the extra light collected made a difference. Tess and I shot some side by side images me with a K-1 her with a K-5. I was never able to prove my point. IMHO the effects of a larger sensor collecting more light are magnified to the point of dishonesty. Especially when the denser pixels of APS-c 4/3 and others is ignored. But even straight up with the same pixel density, I couldn't demonstrate an appreciable difference. "I am such a good photographer that I need more resolution than 12 MP", is quite possibly the conceit of the century.

Hopefully we can now put this to rest.

Last edited by normhead; 11-08-2018 at 06:59 AM.
11-07-2018, 09:12 AM   #176
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QuoteOriginally posted by Ian Stuart Forsyth Quote
The light that the larger sensor captured when cropped will not be used so there is less light going into the image
There is exactly the same light hitting my subject. As demonstrated in the post above this one.
11-07-2018, 02:47 PM   #177
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QuoteOriginally posted by Ian Stuart Forsyth Quote
A very simple test you can do to see the difference in the light that you can gather between using and the whole image is to do this little test

Take you k1 something like 300mm lens and shoot it using iso 100 F8 and the shutter speed the camera selects. Then set your camera to 1.5 crop and select iso 100 and use a lens that would give you the same FOV this would be 200mm but to keep the same DOF you will need to set the lens to F5.3 then notice to happens to your shutter speed and then see what happens if you force the camera to use the same shutter speed?
So two identical fields of view, one with f8 and one with f5.6. So one aperture stop difference. Well guess what, the camera will want to use half the shutter speed for the f5.6 shot compared to the f8 shot. I learned this 40 years ago when I was practising with my MX !
11-09-2018, 06:34 AM - 1 Like   #178
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The folks who identified the weight of the K-1 and the full-frame lenses that go with it (as well as the extra strong tripod/head needed to hold it all up - particularly the 70-200 that comes with its own tripod attaching foot) are exactly right. That is the one big disadvantage to that set-up, in my estimation, but it's all a question of what you're going to use it for. Not exactly a "walking-around" camera, but terrific for portraits, landscapes, etc. And I'm glad I got mine when I did (it was on sale with a rebate that put it below the more recent close-out prices), because I think the K-2 is a disaster. Some of us will remember when McDonald's would sell you a hamburger for eighteen cents - you could also get a cheeseburger, and a coke, root-beer, or orange soda and fries. Those were the only choices and they got big on that basis - now they're just another fast-food joint. The K-2 is similarly drowning in excessive functionality - too many choices. The only thing the K-1 gives me that I really have come to rely upon over the Canon AE-1 is really good autofocusing. If I wanted a point-and-shoot camera that makes all the clever decisions for me, I'd have gotten a snapshot camera. I want to control the aperture, shutter speed, and ISO value myself, I want the color to be "natural", and I don't want the machine "compensating" for how I want to use it. I wanted a full-frame camera because I want as many dots on the "film" as possible for extensive cropping and precision editing, and the K-1 is perfect for my needs in that respect, but overbuilt and top-heavy in clever gim-cracky. It's too smart for its own good but at least the stuff I don't want doesn't get in my way.

On the other hand, the K-50 is a great "walking around" camera, the lenses aren't too heavy, it's relatively unobtrusive and very friendly in its human-interface.

I think that discontinuing both of those cameras was a mistake - too many manufacturers think they have to be constantly "upgrading" their products, when what they really ought to do is work continuously to make existing products that work well and have good market acceptance better. But the need to keep the engineers employed is driving their marketing. I think that's unfortunate, because they're digging themselves into a hole they won't be able to get out of. I got criticized when I was doing software development myself because I switched jobs a good bit. My explanation was that I designed and wrote brilliant, bug-free code that actually did what it was supposed to do. But it's like building a bridge - you don't need the engineer who designed and oversaw the construction of the bridge to hang around and paint the bridge year after year. That guy needs to go on to the next bridge. You get other (and less expensive) people in after the bridge is constructed to maintain and paint the bridge. Pentax could make bigger and better products without sacrificing useful products that already have a following in the market.
11-09-2018, 03:50 PM   #179
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I have a K3 and a K1. I keep both because I have some very good DA* Limited glass that isn't FF-compatible and while I could shoot in APS-C mode on the K1, it's also kind of nice to have a back up camera.

I also have bunch of good FA* glass that was intended for Full Frame so I was glad when I could get a K-1 to get the most out of it.


Having said that, the K-3 feels more intuitive and ergonomic (I have used it longer, it's true) to me. Maybe I'm just less used to the K-1, but it feels a little awkward.


And while the K3 fits pretty well in my hand, it also feels a little unwieldy compared to my first DSLR, the good old K5
11-09-2018, 03:58 PM - 1 Like   #180
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Hi Dlh
Marketing and sheep mentality seem to be the norm now.
Even on this very forum a new camera comes out and the same day threads start up complaining it doesn't have this or that and why wasn't it out earlier and whens the next one coming out.......jeesh
I'm 3 generations behind but it still takes pictures....I'm the stumbling block not the camera

Dave
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