Downsizing

[Hellonearth]

Reading through a couple of topics on the forum I have seen downsizing recommended as a way of increasing the sharpness of a photo. Does this really work? I have read elsewhere that it is something of a myth. Can anyone provide an example and explain exactly how they downsize? Thanks.

 

Kevin

[MDM]

It is nbot a myth - it definitely works -  broadly similar to viewing a large image on a small screen or to viewing an image at a lower size than 100% (zooming out). Similarly if you zoom into an image, it is broadly equivalent to upsizing. You shouldn't really need to see a posted sample as the effect is immediately obvious - just try it out.

 

It can be done in Photoshop in the Image Size dialog by decreasing the number of pixels or exporting from Lightroom to a smaller pixel size. Photoshop has a number of algorithms for resizing images and will automatically choose something called Bicubic Sharper by default when you downsize - the tech details are probably not important to most of us mere mortals.

[John Mitchell]

Yup, it can work well with some images. However, if a shot isn't in focus to begin with, downsizing won't do much good. I use downsizing sparingly, perhaps with one in ten images on average, often due to ongoing QC paranoia more than anything else. Being a mere mortal, I employ the same easy method described by MDM.

[Hellonearth]

Thanks MDM and John for your replies. I will try it but what do I downsize to? Is there a rule of thumb?

 

Kevin

[Betty LaRue]

Sometimes I'll downsize an image from 6000 px longest side to 5000 or 4500. Once in a blue moon I'll take one I hate to let go of to 3000.  

It does work. Like John, I'm a little paranoid and probably do it when it's not necessary. Sometimes I don't trust my own eyes. And yes, it works. I did one in today's upload that looked so much better after downsizing to 4500 px. We'll see if QC agrees. 

Betty

[John Mitchell]

34 minutes ago, Hellonearth said:

Thanks MDM and John for your replies. I will try it but what do I downsize to? Is there a rule of thumb?

 

Kevin

 

No rule of thumb really. I find that 12 MP (4290 pixels on the long side) works well with a couple of my lenses.

 

Some contributors seem to like 4000 or 3800 pixels on the long side. It takes some experimentation. No point in downsizing any more than you have to, though. The lowest you can go and still meet Alamy's minimum size requirement is about 6 MP (3000 pixels on long side).

[Chuck Nacke]

I often downsize, mostly when I shoot NEF (RAW) with D800's at high ISO's

and it appears to work really well, specially when you start with a 7360 by file.

Even with a D800 at 7360 by, if the image is not sharp it will not be sharp at a

smaller size.

[Stokie]

Again, due to QC paranoia, I regularly downsize.

My images come into Photoshop at 5616 x 3744 pixels so I go into 'Image', 'Image size' and just change the 5 to a 4. So instead of a 60.2m size I get a 40.6m size.

 

John.

[John Walker]

From full size images on my Sony RX100 M3, I occasionally downsize to 4000 on the long side.

It makes a big difference when viewed at 100% which what QC is viewing at.

 

John

[KTC]

Downsizing does not improve the image quality itself, you are just seeing less by not "zooming" in as much. So it'll hide things like tiny camera shakes but it wouldn't help out of focus images.

This "works" because images are judge at whatever's full size as submitted so long as they're above the minimum.

[Hellonearth]

Many thanks for all your comments. I will do some experimenting!

 

Kevin