So you guys talk about cropping and size related to percentage and any other advise for the benefit of myself and others on here

[spudhead]

So I often see and have said of shots that I posted this is a huge crop! so in c1 I do not see a reference to size in percentage terms just size in inches or mill, So given the shot below which is from my a7iii and from recent test shots, shot in low light and with silent shutter also not normal for me on this body, its start size is 24 meg 6000 x 4000 the shot is 3219 x 2481 so knowing you guys are smart how do we express that in percentage? and please add your habits on general thought on cropping limits etc

• ILCE-7M3
• Sony FE 200–600mm F5.6–6.3 G OSS (SEL200600G)
• 600.0 mm
• ƒ/6.3
• 1/2000 sec
• ISO 10000

 

[pmenear]

24 meg cropped to 8meg is a 33% crop image. The size of your crop here is a little smaller than the international competition limit of (shortest edge minimum 2500 pixels) which I always stay above. This limit is so the winning images can be printed/published and maintain quality.

 

[spudhead]

Let's start by clearing up nomenclature. "24 meg" is not 24 megabytes, it's 24 megapixels. There are 69MB in a 24MP image.

It'll be interesting to see how many different answers this gets. While the explanation above makes sense (and is the one I subscribe to), I'm not sure it's correct. It doesn't match every explanation, nor does it match my processing program. One problem is it doesn't explain a "100% Crop", which would, under the above explanation, result in zero pixels.

If I check Darktable with my A7 IV starting at 33MP, I find that a 21% crop results in about a 12MP image. Under the explanation above, it should result in about 7MP. Setting a 50% crop results in about 2MP, while one would expect it to be 16.5MP.

If you search the web you'll find varying explanations. Some even state you have to include monitor pixel dimensions in comparison with a 100% image.

I have no idea what the correct answer is here, I wish I did. My post is to point out the differing explanations out there.

As for how far I crop, there is no set point. If the image has begun to look soft or out of focus or if detail is starting to degrade, it's too far. I prefer not to crop at all but that's difficult to accomplish unless you can completely control the environment.

Thanks for replies this is what I was hoping for info in spade loads

 

[spudhead]

24 meg cropped to 8meg is a 33% crop image. The size of your crop here is a little smaller than the international competition limit of (shortest edge minimum 2500 pixels) which I always stay above. This limit is so the winning images can be printed/published and maintain quality.

Thanks for reply great info just what I was hoping for I hope we will get more info and views

 

[Uncle Kevriano]

I always crop in 6 x 4 ratio, which is the same as shot. How far I crop varies obviously. I never pay attention to actual amount of pixels.

 

[spudhead]

I always crop in 6 x 4 ratio, which is the same as shot. How far I crop varies obviously. I never pay attention to actual amount of pixels.

seems to make sense

 

[AlphaWorld]

I always crop in 6 x 4 ratio, which is the same as shot. How far I crop varies obviously. I never pay attention to actual amount of pixels.

Oh, I sometimes crop in a 3:2 ratio, so I guess that must be smaller (because this thread is meant to be helpful, I will point out that 3:2 and 6x4 are the same thing - sorry if that spoils the joke, but …)

In my head, 100% isn’t a measure of cropping, but of scaling. If I crop an image to 3000x2000 pixels, and save it as a 3000x2000 JPEG, that’s 100% - every pixel is in the output. If, on the other hand, I take a 6000x4000 image, without cropping, and save it as a 3000x2000 JPEG, then I have scaled it down by 50%, but I haven’t cropped it at all.

Cropping is about cutting away unwanted parts of the image. Scaling is about making it a convenient size for display.

One of the reasons I like the A7R4 and A1 is because I get images with lots of pixels that I can throw away! I think the furthest I have gone is to crop a piece of just 2000x1000 pixels out of an A1 image (8640x5760).

One of the reasons I would prefer not to talk about cropping in terms of percentage is because I often crop by different amounts horizontally and vertically - sometimes I even crop an image that is longer vertically from an image that is longer horizontally - cropping, say, 3000x4000 out of 6000x4000 - so I have cropped it by half horizontally, but not at all vertically.

Scaling, though, is readily described by a percentage because it applies uniformly in both dimensions (assuming you get it right! If you scale differently you get tall skinny people or short fat people!)

 

[spudhead]

Oh, I sometimes crop in a 3:2 ratio, so I guess that must be smaller (because this thread is meant to be helpful, I will point out that 3:2 and 6x4 are the same thing - sorry if that spoils the joke, but …)

In my head, 100% isn’t a measure of cropping, but of scaling. If I crop an image to 3000x2000 pixels, and save it as a 3000x2000 JPEG, that’s 100% - every pixel is in the output. If, on the other hand, I take a 6000x4000 image, without cropping, and save it as a 3000x2000 JPEG, then I have scaled it down by 50%, but I haven’t cropped it at all.

Cropping is about cutting away unwanted parts of the image. Scaling is about making it a convenient size for display.

One of the reasons I like the A7R4 and A1 is because I get images with lots of pixels that I can throw away! I think the furthest I have gone is to crop a piece of just 2000x1000 pixels out of an A1 image (8640x5760).

One of the reasons I would prefer not to talk about cropping in terms of percentage is because I often crop by different amounts horizontally and vertically - sometimes I even crop an image that is longer vertically from an image that is longer horizontally - cropping, say, 3000x4000 out of 6000x4000 - so I have cropped it by half horizontally, but not at all vertically.

Scaling, though, is readily described by a percentage because it applies uniformly in both dimensions (assuming you get it right! If you scale differently you get tall skinny people or short fat people!)

ok helpful again and yet another point with some common sense remarks just what i was hoping for

 

[Uncle Kevriano]

Oh, I sometimes crop in a 3:2 ratio, so I guess that must be smaller (because this thread is meant to be helpful, I will point out that 3:2 and 6x4 are the same thing - sorry if that spoils the joke, but …)

In my head, 100% isn’t a measure of cropping, but of scaling. If I crop an image to 3000x2000 pixels, and save it as a 3000x2000 JPEG, that’s 100% - every pixel is in the output. If, on the other hand, I take a 6000x4000 image, without cropping, and save it as a 3000x2000 JPEG, then I have scaled it down by 50%, but I haven’t cropped it at all.

Cropping is about cutting away unwanted parts of the image. Scaling is about making it a convenient size for display.

One of the reasons I like the A7R4 and A1 is because I get images with lots of pixels that I can throw away! I think the furthest I have gone is to crop a piece of just 2000x1000 pixels out of an A1 image (8640x5760).

One of the reasons I would prefer not to talk about cropping in terms of percentage is because I often crop by different amounts horizontally and vertically - sometimes I even crop an image that is longer vertically from an image that is longer horizontally - cropping, say, 3000x4000 out of 6000x4000 - so I have cropped it by half horizontally, but not at all vertically.

Scaling, though, is readily described by a percentage because it applies uniformly in both dimensions (assuming you get it right! If you scale differently you get tall skinny people or short fat people!)

I'll clarify. 3:2 is the same ratio as 6 x 4. Basically, in photoshop, it gives the options for crop ratio as standard photo print sizes, so I use 6 x 4 as any prints I do will be that size or a blown up version of that.

 

[AlphaWorld]

I'll clarify. 3:2 is the same ratio as 6 x 4. Basically, in photoshop, it gives the options for crop ratio as standard photo print sizes, so I use 6 x 4 as any prints I do will be that size or a blown up version of that.

Eggzackly.

So 6” X 4” is the same aspect ratio as 12” x 8”, or 15cm x 10cm. Just different scalings (although not a lot of scaling between 6” x 4” and 15cm x 10cm!).

 

[AlphaWorld]

I forgot to mention that I generally make JPEG files from PhotoShop using what I remember as “Save for Web or Devices” (I think they renamed it, but my brain doesn’t keep up with Adobe). On the Mac the default keys are Command+Alt+Shift+S.

In the dialog that pops up, they show the scale factor as % - I usually set the desired number of pixels wide or high, and they show what percentage scale factor that is.

That is why I think of scale factor as a %. I knew there was a reason!

 

[spudhead]

I forgot to mention that I generally make JPEG files from PhotoShop using what I remember as “Save for Web or Devices” (I think they renamed it, but my brain doesn’t keep up with Adobe). On the Mac the default keys are Command+Alt+Shift+S.

In the dialog that pops up, they show the scale factor as % - I usually set the desired number of pixels wide or high, and they show what percentage scale factor that is.

That is why I think of scale factor as a %. I knew there was a reason!

Great stuff just what we need to know helps me understand better so should help others hopefully, thanks for replies

 

[DavidN]

Have you looked at using Topaz Gigapixal AI to up upscale your jpeg file after you’ve cropped/down scaled it in Photoshop? Maybe worth a look to compare quality of final image.

 

[AlphaWorld]

Have you looked at using Topaz Gigapixal AI to up upscale your jpeg file after you’ve cropped/down scaled it in Photoshop? Maybe worth a look to compare quality of final image.

Why would I do that?

If I want a larger version, I would work from the 14 bit RAW file (or saved PSD in 16 bit), rather than start with a JPEG that has been compressed with lossy compression and truncated to 8 bits/channel, after being scaled down.

I don’t understand why you suggest starting from a JPEG?

Oh, is it because that package cannot read RAW or PSD? In that case I’d use TIFF, or another lossless format that can handle more than 8 bit/channel. And I’d start from the unscaled image.

 

[DavidN]

Sorry, I wasn’t suggesting that you start with a .jpg. I assume you shook RAW then crop and edit in post and save the “final” image as a .jpg - is that the case? That’s the .jpg you could upscale in Gigapixal if you needed to.

 

[spudhead]

Sorry, I wasn’t suggesting that you start with a .jpg. I assume you shook RAW then crop and edit in post and save the “final” image as a .jpg - is that the case? That’s the .jpg you could upscale in Gigapixal if you needed to.

I start with raw and edit, and if it needs denoising covert to tiff and denoise and then jpeg for posting, and I am using capture one 22 thanks

 

[AlphaWorld]

Sorry, I wasn’t suggesting that you start with a .jpg. I assume you shook RAW then crop and edit in post and save the “final” image as a .jpg - is that the case? That’s the .jpg you could upscale in Gigapixal if you needed to.

And still I ask, why would I upscale the JPEG? Why not export something that retains more detail, like a TIFF file? Surely this Gigapixel software can accept something better than JPEG?

For that matter, I believe that PhotoShop now has its own upres feature, which I can use, now, because I am using an M1-based Mac (I have only had it a few weeks). And I can apply it to the full resolution image.

The right way to process images is to keep as much detail as possible all the way through your processing, and only scale it down at the very end.

My typical web-ready JPEG is 2500 x 1667 pixels. That’s often scaled down from, say 5000 x 3333 (depending on cropping). And it’s JPEG, so it’s lossy compressed 8 bit/channel. Should I feed that into Gigapixel? Or should I feed in 5000 x 3333 pixels in 16 bit/channel (sourced from 14 bit RAW)? Four times as many pixels, not lossy compressed, and far more detail in colour; it is difficult to quantify the difference between 8 bit and 14 or 16 bit - it is not “double the detail“ = it’s much more, especially when there are gradients involved.

. . .

One time I had someone wanting to use one of my images on her website. She saw it on my phone, and really wanted it. I didn’t mind - it was not an image that mattered to me, so I offered to send it to her when I got home. “Oh, don’t worry, I’ll just photograph it on your phone”… I insisted on doing it properly - I was not going to have my name associated with the image quality that would have resulted.

. . .

I don’t know if I’m alone in being fussy about my image processing.

 

[Ralph]

I am going to say this is all over my head. I don't understand it and I have read it but I am not technical I do things to what I like to see.
Not to what has been said here to what I don't understand one little bit at all.
If if looks good to me then this is what works for me. Yes I can have circles run around me with the percentage talk. And I am okay with that. But the photo posted looks mighty good to me and the talk with it means nothing.
I do things for my pleasure not to do maths subjects after it all.
But well done to those of you who do understand that all.

 

[spudhead]

And still I ask, why would I upscale the JPEG? Why not export something that retains more detail, like a TIFF file? Surely this Gigapixel software can accept something better than JPEG?

For that matter, I believe that PhotoShop now has its own upres feature, which I can use, now, because I am using an M1-based Mac (I have only had it a few weeks). And I can apply it to the full resolution image.

The right way to process images is to keep as much detail as possible all the way through your processing, and only scale it down at the very end.

My typical web-ready JPEG is 2500 x 1667 pixels. That’s often scaled down from, say 5000 x 3333 (depending on cropping). And it’s JPEG, so it’s lossy compressed 8 bit/channel. Should I feed that into Gigapixel? Or should I feed in 5000 x 3333 pixels in 16 bit/channel (sourced from 14 bit RAW)? Four times as many pixels, not lossy compressed, and far more detail in colour; it is difficult to quantify the difference between 8 bit and 14 or 16 bit - it is not “double the detail“ = it’s much more, especially when there are gradients involved.

. . .

One time I had someone wanting to use one of my images on her website. She saw it on my phone, and really wanted it. I didn’t mind - it was not an image that mattered to me, so I offered to send it to her when I got home. “Oh, don’t worry, I’ll just photograph it on your phone”… I insisted on doing it properly - I was not going to have my name associated with the image quality that would have resulted.

. . .

I don’t know if I’m alone in being fussy about my image processing.

I am with you I want to get the best I can from by my shots which is the purpose of asking the questions, I am well aware of the fact that have loads to learn on the editing front but having used the denoise topaz tool for a short while it became apparent quickly that raw with editing done then tiff 16 bit and then jpeg, obviously I am no a pro

 

[spudhead]

Are you kidding me? Your processing is top drawer.

Thankyou I still find myself a bit clueless when I see the in depth replies people post here

 

[Jeff A]

I am one who has trouble following all of the fine points and options. I have been told not to reduce my images smaller than 3840 pixels on the long edge. 3840 x 2160 is 4K. By taking care of the measurement, I'll produce at least a 4K image. That will be good for most people and print well should anyone decide to print one of my images (Not likely )

I will only upload an image to one of two places, this board and Flickr. Most everywhere else will down res the images. The saddest and most aggravating situation is sending a link to a photo or an Album on Flickr and the recipient views them on a cell phone. What a waste!

 

[cjskyler]

So I often see and have said of shots that I posted this is a huge crop! so in c1 I do not see a reference to size in percentage terms just size in inches or mill, So given the shot below which is from my a7iii and from recent test shots, shot in low light and with silent shutter also not normal for me on this body, its start size is 24 meg 6000 x 4000 the shot is 3219 x 2481 so knowing you guys are smart how do we express that in percentage? and please add your habits on general thought on cropping limits etcView attachment 18960

I have been using the enhance feature in lightroom classic and i think in my opinion it does a pretty good job of increasing the pixels by at least 1.5 times or so and helping to keep cropped pics at a fair size in the end