Is there any benefit from down-stepping from highest to lower resolution? (1 Viewer)

Most digital cameras offer the possibility to choose various resolutions. For instance, my camera is a 10Megapixel camera but offers lower levels such as 7Mp, 3Mp. In articles about the "Megapixel myth" we can read that a camera with, for instance 6Mp not necessarily makes less sharp images than one with higher resolution. Indeed the light sensitivity may even be better in the lower resolution camera than the higher due to less but larger pixels on the same sensor area. However, that is when comparing two cameras with different sensors. My question is if there is any gain from stepping down from the highest resolution to a lower resolution on the same sensor? Obviously, there is a gain in number of images that can be stored on the card, and possibly also in the writing speed to the card, but is there any gain in light sensitivity, colour fringing, noise level etc? I assume few camera sensors offer the possibility of combining pixels, right?

The only sensor which I have used that gave me tangible improvements under certain circumstances by reducing its resolution is the EXR sensor in the likes of the Fujifilm HS20.

Other than this some early/cheap digital cameras interpolated to get their maximum resolution which was fairly terrible, so you were really just as well off sticking to the lower resolution.

Some cameras can improve their shooting speed and/or number of shots buffered by going down to a lower resolution.

I believe that some cameras give you an increased digital zoom by using the pixels you were not using by dropping the resolution, though whether this is an improvement over simply cropping I am not sure?

Any other thoughts, corrections etc?

613Orm said:

Most digital cameras offer the possibility to choose various resolutions. For instance, my camera is a 10Megapixel camera but offers lower levels such as 7Mp, 3Mp. In articles about the "Megapixel myth" we can read that a camera with, for instance 6Mp not necessarily makes less sharp images than one with higher resolution. Indeed the light sensitivity may even be better in the lower resolution camera than the higher due to less but larger pixels on the same sensor area. However, that is when comparing two cameras with different sensors. My question is if there is any gain from stepping down from the highest resolution to a lower resolution on the same sensor? Obviously, there is a gain in number of images that can be stored on the card, and possibly also in the writing speed to the card, but is there any gain in light sensitivity, colour fringing, noise level etc? I assume few camera sensors offer the possibility of combining pixels, right?

Click to expand...

Good question....at least for on-screen images some of the older and far simpler (in terms of pixel count imaging options) cameras gave as good or better images than some of todays more complex cameras.

Very true Dave - I was looking at my pictures of Venice shot in 2 Megapixels when that was considered pretty good and they look fine on my 2 megapixel computer display screen as long as you don't go pixel peeping.

I must admit the later upgrade to 5 megapixels was welcome though for all sorts of reasons!

Many Fujifilm HS20 user shoot permanently on half resolution (8Mp) to get the full benefits of expanded dynamic range/low noise on the EXR sensor.

I actually like lots of usable pixels, its just that I can't afford a Pentax 645D, Hassleblad etc., that handle them really well and to be honest, I don't think that the people who get to see my pictures would notice the difference!

It really depends on the final use of the image.

For posting on the web all you need is 900 pixels on the longest side, so a 900x600 image is just 540,000 kb or 0.54 megapixels. At 300 ppi, this image would be best printed at just 3 inches by 2 inches so you lose some quality if you want anything much bigger than a very small print, but for the web it is just fine. . Now the advantage of a larger file is you have more latitude to sharpen, remove noise, or cover up slightly out of focus images when you reduce the image in size. So there is some benefit of having a large file.

On the other hand, if you want a nice 8x10 inch print, you need a file that is 2400 pixels by 3600 pixels (the camera has a native file with a 3:2 ratio, so the file needs to be 8x12 inches and 300 PPI) or 8.64 megapixels. Anything smaller and you are going to need to upsize the file - which upsizes noise, blur, etc. and loses a bit of resolution. So a larger file of at least 8 MP is needed for an 8x10 print. Now these proportions are conservative so you can always make a little larger print without issue - but much larger than 12x18 inches would start to be a problem with an 8 megapixel file.

Now if you shoot RAW - for most cameras the file size is at full resolution. The only way you can reduce the file size is to create a JPEG rather than a RAW file. With JPEG's you can vary the size of the image and the quality to reduce the size. A RAW file gives you the maximum ability to edit the image and control quality. So if size is an issue, it is better to have a RAW file which at least will optimize what you have.

300 PPI isn't the minimum resolution for a good print: it's the point at which any increase in resolution becomes undetectable by eye. In practice, a 200 PPI (6MP) print is perfectly good under normal viewing conditions (50cm minimum viewing distance).

Many cameras allow sRAW (reduced resolution RAW), so that's not necessarily an argument either.

On the other hand, downsampling a high resolution files gives much the same benefit in terms of noise reduction as a reduced resolution image from the camera would.

Reduced resolution will give no benefit in reducing colour fringing. The fringing may be fewer pixels wide, but it's still the same width in relation to that against the sky twig or TV aerial.


If you reduce camera resolution, the advantages are:
a) reduced storage requirements
b) longer bursts before hitting buffer limits

The disadvantages are that you are eliminating options for using your image.
You have a reduced ability to crop and still get a good print. Attempting to avoid this by shooting full frame in the first place (if you can get close enough) will lead to a good number of failures due to the end of the beal ot wing tip being out of shot.
You have a reduced ability to get a really big enlargement of your good shots (poster size on the wall)

Thanks for all the answers!
So, if I understand correctly, the benefits with in-camera choice of lower resolution is mainly the gain in burst speed and memory capacity, as well as the possibility of cropping the image, but that there may also be some gain in reducing noise (although it would be the same if down-sampling a higher resolution image in the computer later on.
Well, I guess I set my camera on the highest resolution so I have better possibilities for cropping. Memory is not a problem nowadays with SD cards of several Gigabites.

I think the issue of using lower resolution is when the shots are being transferred to the memory card, the camera is unable to take any more, so smaller files = quicker to write to card