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Resolution advantage over lesser lens performance?

Stevieraveon

New member
I read a comment somewhere that when you shrink a super high resolution image down to a smaller one it will look better than one made with a smaller sensor. (say a medium format vs small format film parallel in same print size)

Anyone care to comment?

The driver for me is that most of my clients do not necessarily require all 60 megapixels so if I am prepared to shrink my images, does that pick up the slack where a lens is not as sharp at pixel level? (Please don't shoot me for willing to compromise the pursuit of utmost pixel level perfection in this forum :deadhorse:)

In real life translation, I am looking at lens choices for the Phase One 645 DF+ and am wondering the impact of image size reduction in the overall equation comparing newest lenses with older (say latest Phase One or SK lenses vs. older Mamiya M645 N lenses) and whether I can get away with softer lenses with this.

As a side note I observed a photographer who provides low res images in the format of 30 dpi but at 8000 pixels. I take it this is intentional but what is the benefit here?
 

shlomi

Member
I read a comment somewhere that when you shrink a super high resolution image down to a smaller one it will look better than one made with a smaller sensor. (say a medium format vs small format film parallel in same print size)
You are confusing (or the original poster was) between sensor size and pixel dimensions. If you take two pictures with same size sensor, one with high resolution and one with low resolution, and then downsize both of the to a size smaller than the smaller one, then there will be no difference in the result.

If, on the other hand, you are taking a picture with two sensors, both at same pixel dimensions but different sensor size, then there will be a difference between the two pictures, no matter how the pixels are resized, because the difference comes from optical characteristics.

The driver for me is that most of my clients do not necessarily require all 60 megapixels so if I am prepared to shrink my images, does that pick up the slack where a lens is not as sharp at pixel level? (Please don't shoot me for willing to compromise the pursuit of utmost pixel level perfection in this forum :deadhorse:)
Most clients don't need 60MP - give them the file size you think they need or want. Files that are too big many times cause problems for the clients to process with their puny computers. Other clients are pixel hungry and you should give them as many pixels as you possibly can. It is up to you to know which is which.


In real life translation, I am looking at lens choices for the Phase One 645 DF+ and am wondering the impact of image size reduction in the overall equation comparing newest lenses with older (say latest Phase One or SK lenses vs. older Mamiya M645 N lenses) and whether I can get away with softer lenses with this.
Be specific what focal lengths you are talking about and what lens models - each one if a different story.
In general - N generation lenses are not only softer not also have different colors (contrast), and may give your image a look that is unsatisfactory.

These are the generations of lenses:
LS - latest - very expensive
Phase One D - less expensive but IMO just as good (for my applications - I know there are differences under some parameters)
Mamiya D - some are older and softer than Phase One D, other are newer and the same quality
Mamiya AF - depends on the lens - many are much softer
Mamiya N etc. - must manually close down aperture every exposure - to me that is unacceptable workflow - some lenses are not very different optically than the AF generation.


As a side note I observed a photographer who provides low res images in the format of 30 dpi but at 8000 pixels. I take it this is intentional but what is the benefit here?

8000 pixel is high resolution. If the photographer attached 30DPI value to the file, it doesn't change anything regarding the pixel matrix in the file. You can specify any DPI that you want to a file before you print it, and that is the only time when it becomes relevant. Pixel dimensions on the other hand - once you decrease them, you can't increase them again without degrading the picture.
 

Stevieraveon

New member
You are confusing (or the original poster was) between sensor size and pixel dimensions. If you take two pictures with same size sensor, one with high resolution and one with low resolution, and then downsize both of the to a size smaller than the smaller one, then there will be no difference in the result.

If, on the other hand, you are taking a picture with two sensors, both at same pixel dimensions but different sensor size, then there will be a difference between the two pictures, no matter how the pixels are resized, because the difference comes from optical characteristics.
Shlomi, thank you for the response. It is well done and answers my question. I tried to think back on the comment I read. I think the original posting person was saying that when you take film medium format and small format and print them to the same small size, the medium format image will look more detailed and contains more gradation. Looks like resolution and your optical gain explanation clarifies this. I am just unsure if downsize interpolation can benefit from larger original pixel count. From your explanation I guess it doesn't.

Be specific what focal lengths you are talking about and what lens models - each one if a different story.
In general - N generation lenses are not only softer not also have different colors (contrast), and may give your image a look that is unsatisfactory.
Thanks for the breakdown. I am waiting for the rumored wide zoom that may be announced at end of year hence wondering if I can get a cheaper prime to tie me over till we see the performance and the spec of the zoom. I am looking at the Phase One 45mm D and the Mamiya 55mm f2.8N which seems like the sharpest of the bunch. The resolution reduction benefit was my original query on whether I can leverage it as a benefit. I know the N will be softer and less contrasted.

8000 pixel is high resolution. If the photographer attached 30DPI value to the file, it doesn't change anything regarding the pixel matrix in the file. You can specify any DPI that you want to a file before you print it, and that is the only time when it becomes relevant. Pixel dimensions on the other hand - once you decrease them, you can't increase them again without degrading the picture.
I must apologize I did not get the facts right before asking this question. So I went back and checked the file, they were indeed 8000 pixels at 300 dpi. (I understand dpi and the "non-impact" on resolution) The thing is the jpg compression was set to 1. I usually understand low res images as 800 or less pixels with compression of 6 to 9. The high pixel super compression was also what triggered my interest in what high pixel count does to the quality of an image.
 
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GrahamWelland

Subscriber & Workshop Member
If you get the 45D I'd question the wisdom of getting a 55mm unless it is the excellent 55LS (which is razor sharp).

With the DF I find that less lenses are preferable to more (and I have just about all of them). I'd consider a spread of lenses and zoom with your feet vs a plethora do focal lengths or zooms.
 

Stevieraveon

New member
Shlomi, thanks for your insight.

Graham, I am only intending to buy one lens in the meantime either the 45 or the 55 before seeing the wide zoom spec. Thanks for the note on lens choice with close focal lengths, yes it is true. I was looking at the Hasselblad 40 CFE at one point but the distortion is pretty bad... actually distortion is bad for all wide angle MF SLR variants compared with Tech camera lenses.. something I've just come to understand.:cussing:
 

Stevieraveon

New member
Thanks Shlomi, the more I think about it I am leaning towards this as well since I use the 43XL the most on my interior shoots and 55 is a bit too long. I was trying to save money before seeing the details on potentially 40-80 zoom but I guess the 45 prime will be handy in the arsenal in the long run. I guess I am in the hunt for a used one then.
 

Stevieraveon

New member
I may have found a reason behind high pixel high compression image format. I see facebook supports images up to 2048 and they typically apply high compression of 80% or so. My guess is this format of "low res" images is for sites that limit by file size and not pixel dimensions perhaps.

Any thoughts?
 

shlomi

Member
Frankly if you're using high compression then there's not much point to an IQ back.
It deteriorate the image and should never be used.
You should reduce the pixel dimensions and increase the compression moderately and never extremely.
I think this is why you didn't get many other responses - you seem to be missing a lot of your basic knowledge, which is assumed when you use this type of equipment.
 

Stevieraveon

New member
Thanks Shlomi

I guess I need to clarify and probably put into a different thread as I was adding this to the end of original question. I should have made a post called effects or potential advantage of large resolution images in potential benefits to: making up for lens performance or downsized online uses.

Thanks for your answer to the first part, for the second part, this is my reasoning.

I, along with other photographers I know supply high res and low res images to our clients for convenience. I usually supply full res tiff for publication and in addition low res so they can email, post to blogs, websites or use as award jury submissions. I format them as compressed jpg (800 pixel compression of 9 and appropriate sharpening for this size - which is what Getty supplies for low res stock images.)
 

shlomi

Member
For email you should provide 1000 pixel 80% save for web.
Save as jpg is larger and contains some information that is needed only for printing.
Save for web is an option in the save menu above save as jpg.
 

Stevieraveon

New member
Thanks Shlomi.

I feel this post is getting derailed from what I am trying to ask. I do think I have a good understanding for digital imaging output for print and digital use. I have a few ways to achieve low res images. Personally I mostly use Adobe bridge which lets me batch process images using image processor tool for photoshop. I have written various actions in relationship to desired images size which includes SRGB color space conversion, 8 bit depth conversion, image dpi specification and appropriate overlay sharpening. Ultimately we all have our preference for what we consider a low res image based on practical end use.

Perhaps I can ask this question in a different way for some thoughts.

Why would an established photographer choose to provide "small" images at large pixel dimensions with very large amount of compression? It is obviously an intentional choice on his part.:confused:
 

Stevieraveon

New member
Same reaction from my side when I first saw that. Well I did a quick test with my image to see the pros and cons of this unusual setting.

I made 2 versions - one at 8281 pixels with compression of 1 (a), the other 800 pixels at compression of 9 (b).

On screen - benefit is user can zoom in and see the details. Gradation is pretty bad in a smooth surface but texture is surely there. (b) How we all understand a low res image is like, not much zooming before pixelization happens.

In print - I printed both at 10 inches and results is as expected. (a) has much more fine details and textures, edges look good everything appears sharper but one gets blotchy shadows and highlight with banding. (b) has blurry edges/aliased stepping lines, lack of textural details but smoother gradation and more highlight shadow details and dynamic range.

My only intelligible guess is that it packs more detail in a somewhat manageable file size. Since most people values / judges an image quality by acuity over gradation, it can have the illusion of a better image at this setting. The large size is handy for people to be immersed and convey details in use. It is probably not good for online piracy although the only precaution is the punishment of blotchy gradation which makes lousy prints.

In a way he is leveraging the higher resolution from the back for a particular advantage.
What do you think?
 

shlomi

Member
Most people view proof on their screen so the normal way works.
Maybe his clients want to view their proofs printed on 10" - why would they want to do that I do not know. Maybe he prefers that his clients view their proofs printed rather than online.
 

Stevieraveon

New member
These are not proofs. They are final images on the disk. There are high res and low res included in the package. The low res is meant for convenience use.

The 10 inch was just an arbitrary number I picked for my own test...

It just dawned on me I never talked about the application. This is for commercial architectural and interior photography where design details is of importance.
 
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ErikKaffehr

Active member
Hi,

What I have seen is that if an image is shrunk, it will keep MTF but it will limit resolution.

So the image will look sharper, but contain equivalent detail.

Sharpening also comes into play, sharpening can boost MTF but it may come with some additional cost. So there is no simple answer.

The DPI (should be PPI) is just a note of itent. The only thing that matters is the number of pixels.

Best regards
Erik



I read a comment somewhere that when you shrink a super high resolution image down to a smaller one it will look better than one made with a smaller sensor. (say a medium format vs small format film parallel in same print size)

Anyone care to comment?

The driver for me is that most of my clients do not necessarily require all 60 megapixels so if I am prepared to shrink my images, does that pick up the slack where a lens is not as sharp at pixel level? (Please don't shoot me for willing to compromise the pursuit of utmost pixel level perfection in this forum :deadhorse:)

In real life translation, I am looking at lens choices for the Phase One 645 DF+ and am wondering the impact of image size reduction in the overall equation comparing newest lenses with older (say latest Phase One or SK lenses vs. older Mamiya M645 N lenses) and whether I can get away with softer lenses with this.

As a side note I observed a photographer who provides low res images in the format of 30 dpi but at 8000 pixels. I take it this is intentional but what is the benefit here?
 

Stevieraveon

New member
Thanks Erik, I think this is exactly what I was trying to remember and clarify. So if we look at the same print size the one made with larger format cameras will still have image quality benefit (MTF as you noted) and this is due to resolution benefit and optical system as Shlomi noted. So I was wondering if one can leverage this and get away with a less sharp lens since it kind of gains over a smaller format if one is willing to downsize the final images for use. Anyhow I ended up purchasing the D lenses which is a better decision in the long run but seems like it potentially could.

Is there any other benefit for a super high res sensor to leverage against if one is willing to downres? I happened to read this on Ming Thein's post this week about the Pentax 645.

"consider this: if at the pixel level it loses a stop or two in noise to the D4S, but has nearly four times the pixel count – downsampling is going to yield an amazingly clean image, regardless of the ISO used, with that medium format look*. And that makes things interesting.
*Related to the depth of field properties of the actual focal length of the lenses, and irrespective of the field of view. Smaller formats mean shorter focal lengths for the same equivalent FOV, and the attendant depth of field properties that go with it – i.e. a lot."

So I see the benefit of noise masking, anything else? Does it mask camera shake or out of focus shots?

Yes sharpening is a different topic altogether, appropriate to final size and medium indeed.
 
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