Why diiferent sizes of pics?

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This topic contains 11 replies, has 4 voices, and was last updated by  Hywel 9 years ago.

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  • #25815

    Doug340
    Participant

    This is a question about something that I have been curious about for some time. In the archived set today, “Losing her Cherry (Part One)”, the first picture is almost 4 megs in size, while all the other shots are around 200kb. Why do you do that? Also, sometimes there are two downloads possible of pictures, typically called regular or large, sometimes called hi-def, etc. Again, why sometimes and not at other times?

    #25816

    Sablesword
    Participant

    It’s a legacy of how photo resolutions have increased over the years. At first, all the photos in new sets were of “regular” size. Later, the new sets had all the photos in the set at “regular” size, with a few of them in both “regular” and “large” size. Still later, new sets were offered in two sizes, “regular” and “large,” as with the current updates. Which type an archive set is depends on what era the set is from.

    #25817

    Hywel
    Keymaster

    … what Sablesword said! Perfectly put 🙂 thank you!

    Cheers, Hywel

    • This reply was modified 9 years, 2 months ago by  Hywel.
    #25833

    Doug340
    Participant

    OK, thanks, that explains the history. But what was the reason one or two pictures were so large in the first place? I mean 4 megs vs 200kb.

    #25834

    Hywel
    Keymaster

    The large pictures are at the resolution they came off the camera.

    In the very earliest days, the resolution of pics was limited by the scans you could get done of slide film as it was processed. People had limited size screens, bandwidth of internet connections was very limited, and storage space for the images was expensive.

    My first digital camera had 3.1 megapixels: 2160 x 1440 pixels.
    At the time, screen resolutions were generally 800 x 600 pixels, maybe 1024 x 768.
    So I down-sampled the images to what felt like a good compromise between resolution and file size.

    In the following decade, digital SLR sensors rocketed up in resolution by a factor of 10 or more. So a modern Canon dSLR, the equivalent of my original D30, now has more like 20 megapixels: 5472 x 3648 pixels or so.

    In the same time, bandwidth has gone up and storage speed has gone down. Screen resolutions have gone up a bit- a more routine screen size would now be 1600 x 1200 or 1920 x 1080 or so. A few high-res screens are getting up to 3840 x 2160 (the new iMac is even higher). But people are also viewing the site on mobiles and tablets whose resolution is still more like 800 x 600 pixels.

    So in the modern era, it is worth me putting up full resolution pictures (6496 x 4872 for the Hasselblad) for people with “4K” or “UHD” screens and people who like to zoom in to see every little detail. But the download times are still significant for those, and it is overkill for anyone looking at the site on a mobile phone, so the regular size images (we settled on 1600×1200 pixels) are still right for a lot of people.

    In the middle of all these huge technological changes, there was a point where some people had higher resolution screens or the desire to zoom in, or the desire to print out in high resolution for their own enjoyment. But connection speeds and the cost of storage space on the web server had not reached the point where it was a sensible or cost-effective proposition for me to put up ALL the shots from every set in full size and well as regular size.

    So as a “treat” or bonus, I put up large versions of a few of the images from each set, the ones I thought were the best and the most striking.

    When connection speeds and storage costs reached the stage that putting all the full-size versions up for each set was a sensible proposition, we started doing that.

    So it is a historical accident of a point in time where it wasn’t possible to put up the full res versions of everything but people had expressed interest in having them for at least some photos in each set.

    If time or money were in greater supply, I’d probably go back over all the old sets and reprocess them to get full-sized versions of all the archive sets done as well. Unfortunately that’s very time consuming and the returns on doing so would probably not be a sensible business proposition. I might do that if I ever retire from shooting new stuff, but until then, the new stuff has to take priority!

    Cheers, Hywel.

    #25842

    Sablesword
    Participant

    The regular pics in that set are 960 x 1280. The big pic is 4872×6496, which is ~25 times as many pixels. So the filesize will be ~25 times a large given the same degree of compression.

    If you’re asking why the big pics are 4872 x 6496, I belive that’s the full resolution of RE’s big Hasselblad camera.

    #25843

    Doug340
    Participant

    Ah, that all makes sense now, Hywel. Thank you.

    For what it is worth, my preference is to have the option of two resolutions of the same set of pictures, so I can decide which to download. Particularly if the model is Ariel, I always download the higher resolution pictures if I have a choice. But in the case of other models I would be more choosy. These days storage is so inexpensive it barely makes a difference however, since I have added another 5 TB just this past week and have a central server of over 20 TB now (for all sorts of material) which I fully expect to grow even larger. {I was somewhat surprised to discover that I have over 1 TB of Ariel alone, in her several personas, videos and pictures all in). I imagine many others, including hobbyists like myself, are similarly situated.

    I am also an audiophile and have over 5000 LPs (which I play exclusively on vacuum tube, a.k.a. valve, equipment for the sweet and holographic sound still not realizable via digital playback). However that collection requires a wall of shelves in my main listening room which is 15 feet long and 6 feet high. By way of comparison, my central server and associated equipment is less than half the size of a case of wine!

    #25970

    Dorsai6
    Participant

    If time or money were in greater supply, I’d probably go back over all the old sets and reprocess them to get full-sized versions of all the archive sets done as well. Unfortunately that’s very time consuming and the returns on doing so would probably not be a sensible business proposition. I might do that if I ever retire from shooting new stuff, but until then, the new stuff has to take priority!

    Hum… If this doesn’t require specialized equipment, could you farm it out to volunteers? I have no idea of the complexity of the manipulations required. I suspect it’s more than just resaving images at a different resolution. On the other hand, if it is a process that can be reduced to an algorithm or procedure others might be able to help.

    For example, I have a medium grade Mac Pro (late 2013) and a lot of disk storage. I also have Adobe PhotoShop CS6 and I’m very skilled at writing AppleScript applications to automate tasks requiring the use of multiple applications and multiple steps. On the other hand, I have very little artistic sense and only limited experience in using PhotoShop.

    You might try an experiment with some volunteers: Send them a few images or a photo set with instructions and see what results you get. You might need a contract to protect your rights to the images themselves.

    #25996

    Hywel
    Keymaster

    I think it is more to do with my anal inability to let go of doing the final pass on all the photos myself, to make sure they look the way I want them to look. Although I sometimes let go of the airbrushing part of the job (indeed I have tried farming that out to other people in the past) the final colour correction and look-and-feel pass, the little adjustments to each shot and the overall look applied to the set… I just want to do myself.

    Sadly no algorithm or instructions to anyone else can quite get over the “adjust so it looks RIGHT to Hywel’s eyes” process, I don’t think!

    Cheers, Hywel

    #25997

    Dorsai6
    Participant

    Hywel,

    I’m really glad to know that every photo gets your personal attention. I don’t have the skill or experience to even do some airbrushing. On the other hand, if you ever think some AppleScripts might lighten your workload, let me know. AppleScript is an area where I have some useful competency. Programming is often a useful solution for repetitive work that doesn’t require human judgement.

    #25999

    Hywel
    Keymaster

    Thanks… I think the process is already automated as far as it can be (I’ve had a BIG incentive to search out efficient workflows, given the volume of photos we shoot each month).

    Most of it is automated inside Hasselblad Phocus and Apple Aperture, for the stuff that remains relatively constant over photos in a set. I make the adjustments to things like colour temperature, tone curves, sharpening, vingette, etc. on one “typical” photo from the set then paste over all the others in the set. I then do a quick scan though by eye to match exposure levels and to crop if necessary.

    For example closeup shots are almost always a stop underexposed compared with the rest (it’s a function of the way the optics work, despite the nominal constant aperture). Shots from opposite sides of the model might look more consonant with a third of a stop difference, etc.. Again this is all automatable- find one prototype shot and paste the settings onto others.

    The airbrushing has to be done shot by shot. Typically I smooth out skin blemishes aiming for the final shot looking like the model on a really good day. So I try not to remove moles and similar distinguishing features but would get rid of bruises, zits and scrapes. I do sometimes remove moles as well but usually only do so if the lighting is causing undue prominence. I try to be fair to one’s visual impression of the model- if the light is making a mole look like a mountain, but you wouldn’t even notice it to meet her in real life, I’ll try to tone it down a little in photos.

    I run most photos through a very very light skin smoothing pass as well, using an automated plug-in with the settings turned pretty much down to minimum. This is really just to give a nicer basis for the airbrushing step, and to even out some of the unfairly harsh effect the lack of an anti-aliasing filter on the Hasselblad sensor can have on skin, especially in closeups. I don’t consider this to be cheating because most other cameras do the same effect optically with their low-pass filters, so I’m just reproducing the look in a more controlled fashion in post.

    Keywording, selecting previews for sets etc. is all done in Aperture too, as is the final export step which includes all the resizing, adding logos, etc. – all automated already.

    Cheers, Hywel.

    #26000

    Hywel
    Keymaster

    P.S. I also do all of this for shots taken for the site by other people, incidentally. So shots done by Steve or Alexander Lightspear I take as RAW and do all the post processing as if I’d shot them myself

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