Scenario: Crop vs Full Frame Sensor RE Image Cropping

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DragonGraffix

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Hopefully you kind folk may be able to answer a conundrum:

Lets say a crop sensor DSLR with a crop factor of 1.5 produces a 12MP image using a 200mm lens with an effective focal length of 300mm (like my Nikon D90).

Lets say that a full frame 24MP sensor DSLR (like the Nikon D600) uses the same 200mm lens (giving an effective focal length of the same 200mm) to give a 24MP image.

Now lets say, at the editing stage, the image from the full frame sensor 24MP DSLR is cropped down to give the same size image as the image from the crop sensor camera (ie they both look like 300mm images) and the resulting cropped image is 12MP (like the crop sensor DSLR image).

So, in summary, we have 2 images, both 12MP, both look identical, one taken with a 12MP crop sensor DSLR, and one taken with a 24MP full frame sensor DSLR, but cropped at the editing stage.

Which of the 2 images would be better quality and why?

Thanking you in advance for any answers you may be able to give! :)
 
DragonGraffix said:
So, in summary, we have 2 images, both 12MP, both look identical, one taken with a 12MP crop sensor DSLR, and one taken with a 24MP full frame sensor DSLR, but cropped at the editing stage.

Which of the 2 images would be better quality and why?

Thanking you in advance for any answers you may be able to give! :)
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Well... The 24MPix image wouldn't become 12MPix, the crop factor is about 2.25. Assuming you are not blowing the image up so you can see the effects of the pixels, and the sensors are the same "quality" they will look identical.
 
The reason I ask the question is that I have a 12MP Nikon D90 crop sensor. I am thinking of upgrading to a Nikon D600 full frame sensor. I do a lot of telephoto lens work. The benefit of the D90 is that I get a 1.5 effective focal length increase. However, if I was to buy a full frame sensor camera, and crop my images to give the same effect of the 1.5 X increase, would I benefit or loose out on image quality? :)
 
The D600 cropped images will be better quality. It's a much newer tech sensor, and even cropping in PP is just like blowing the image up a little, it'll still be FX quality.

I too have a D90, and got a D800 a few months ago. I know I'd notice the difference between a similar image from the D90 and a cropped D800 one. Course, the D800 is a megapixel beast.
 
Cagey75 said:
The D600 cropped images will be better quality.
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If the sensors are exposed well, and not fighting for light (so you are at a sensible ISO/exposure) you will not be able to tell them apart.

Cagey75 said:
It's a much newer tech sensor, and even cropping in PP is just like blowing the image up a little, it'll still be FX quality.
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When you crop, you make the sensor"DX quality". It is the area of the sensor and how much you blow it up to make the picture you look at that matters.

Cagey75 said:
I too have a D90, and got a D800 a few months ago. I know I'd notice the difference between a similar image from the D90 and a cropped D800 one. Course, the D800 is a megapixel beast.
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In good light, you'd probably find it hard to tell them apart....
 
arad85 said:
If the sensors are exposed well, and not fighting for light (so you are at a sensible ISO/exposure) you will not be able to tell them apart.

When you crop, you make the sensor"DX quality". It is the area of the sensor and how much you blow it up to make the picture you look at that matters.

In good light, you'd probably find it hard to tell them apart....
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What about in bad light?
 
To put simply.. I have a 1dmkIV which is a very good dslr on a crop.. I ahve a 1dx with full frame... both using the same lens i prefer the 1dx full frame cropped in more to get the same pic as the crop camera with less cropping.. I presume the fact its FF gives better quality...
 
DragonGraffix said:
Hopefully you kind folk may be able to answer a conundrum:

Lets say a crop sensor DSLR with a crop factor of 1.5 produces a 12MP image using a 200mm lens with an effective focal length of 300mm (like my Nikon D90).

Lets say that a full frame 24MP sensor DSLR (like the Nikon D600) uses the same 200mm lens (giving an effective focal length of the same 200mm) to give a 24MP image.

Now lets say, at the editing stage, the image from the full frame sensor 24MP DSLR is cropped down to give the same size image as the image from the crop sensor camera (ie they both look like 300mm images) and the resulting cropped image is 12MP (like the crop sensor DSLR image).

So, in summary, we have 2 images, both 12MP, both look identical, one taken with a 12MP crop sensor DSLR, and one taken with a 24MP full frame sensor DSLR, but cropped at the editing stage.

Which of the 2 images would be better quality and why?

Thanking you in advance for any answers you may be able to give! :)
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I have done this test with a canon 1ds2 (17mp) and a 1d3 (10mp)
the files were the exact same at 100% view, the extra 7mp on the 1ds were only giving me extra 'width' not extra resolution (resolution meaning ability to see fine detials)- you'd have to quadruple the mp count to 40mp to see a 2x increase in resolution

so there will probably be no difference in terms of 12mp crop to 24mp full frame, crop that 24mp full frame image down to 1.5 crop and you're left with 10.5mp- essentially the same as the camera you currently own
you'd have to step up to the d800 to be able to crop by 1.5 and still be left with 15mp- and even that is a tiny increase over your current camera

mega pixels are the work of spin doctors, the dramatic increase in mp count doesn't actually mean much i terms of image size

d7000 with 16mp crop is actually a better option for tele work than the d600- i'd say the d7000 and d800 should be comparable in terms of resolution potential if you're cropping the d800 files by 1.5x
but then of course you are always cropping the d7000 files where as the d800 you can choose to crop or choose not to crop

I shot my 1ds2 as if it had a 1d3 mode built in- I couold crop down to 10mp and shoot wider when I needed to

DragonGraffix said:
What about in bad light?
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make bad light good- by using flash, VR, fast lenses, tripod

shooting in the dark is over-rated, it produces poor images, use flash
 
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DragonGraffix said:
What about in bad light?
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Right.

Assume the sensors are identical in performance. If you crop to the same size, after you are taking the picture, there is no difference because cropping just makes the sensor the same size. If one sensor is better than the other, it will show in low light.

You cannot tell which will be better when cropped by the original sensor size. It simply comes down to which is the better sensor in low light. A good crop sensor will beat a bad full frame when the FF is cropped to the same size.
 
TBF, if you're taking photos of the visible surface of the moon, it's in full daylight ;)

Spot on about night time cityscapes, though (I did a few myself this very evening). Plenty of other situations when you can't use flash - railway operators take a dim view of it and it will likely lead to your swift departure from the premises.
 
KIPAX said:
or your night time city landscapes :)
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i'd use long exposure on a tripod and a 24mm 1.4 before I ever shot at iso 51,200

and night time shots- if you leave the shutter open for about half an hour and don't fog the frame with light polution it looks just like daytime, so here's a couple of minutes in the pitch black, f2.8 iso 200


Exhibition Centre Panorama by pretty in pixels, on Flickr

obviously not going to work if you need to freeze motion though


and maybe sometimes you've just got to say ok I won't take this photo because I don't have the capability to do it justice
 
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Musicman said:
TBF, if you're taking photos of the visible surface of the moon, it's in full daylight ;)

Spot on about night time cityscapes, though (I did a few myself this very evening). Plenty of other situations when you can't use flash - railway operators take a dim view of it and it will likely lead to your swift departure from the premises.
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what I mean about using flash is more for events, or anywhere where you're allowed to take photos

like here

Backstage at Royston Blythe by pretty in pixels, on Flickr
no flash, grainy, struggling to get good exposures

or I could put on a flash and get noise free images that are better lit
flash is under-rated, everyone's all like ISO ISO ISO ISO when I think people should think about flash more and learn to use it to balance natural light exposure
470811_194851727315588_1765269504_o.jpg


yeah my camera sucks at high iso- but had I a 1dx it still would produce a pretty naff image in those conditions becasue the lighting was so horrible, mixed colour temperatures and patchy- take away that light and replace it with something you can control
 
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mrjames said:
or I could put on a flash and get noise free images that are better lit
flash is under-rated, everyone's all like ISO ISO ISO ISO when I think people should think about flash more and learn to use it to balance natural light exposure
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where is flash under-rated, I don't pick that up from anywhere?
 
ernesto said:
where is flash under-rated, I don't pick that up from anywhere?
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Me neither.

Flash is inappropriate in many situations though, which is where good high ISO capabilities come into their own.
 
ernesto said:
where is flash under-rated, I don't pick that up from anywhere?
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because the ratio of threads talking about high iso vs flash are probably like 10:1, everyone's like ok i'll drop an extra £1000 to get a little better high ISO, when really you can get better results with a £100 flash gun

yeah you're right flash is innappropriate for some occasions, but I think people get so hung up on ISO they forget that flash is appropriate in ANY situations

fuji x-e1- built in flash tilted up to the ceiling, get in get the shot and get out, simple and perfect
 
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