Thursday, 8 March 2012

Not quite a year, or is it?

I suppose, given that we got a free day this year (Feb 29th), it might be considered a year since I last posted, but as it's not the 9th until tomorrow, I'm saying it's not quite. ;)

Anyway, yes, I've not been posting.  As usually happens, work has been getting in the way (not that I'm complaining, I've shot some beautiful people over the last year and produced a good number of images I'm rather proud of).

I've been teaching some workshops too, and have also recently relaunched an old site under the new guise of learning photography, so I will generally be posting there from now on.  I'll also be rewording and updating some of the stuff on here and shifting it over there in the form of new posts.

So, head on over to http://www.diyfilm.co.uk/ and start following there instead. :)

Wednesday, 9 March 2011

DPI vs. PPI - And why it matters, or not. :)

Hi folks. Yes, I realise I said I was going to post more, but things don't always work out the way they expect, so no more promises from here on in. I'll post as and when I feel I want to post something. That maybe twice in one week, or I may go 6 months between posts. But anyway.

I had a little back and forth with Scott Bourne on Twitter (@ScottBourne) regarding a new article on his site about why PPI doesn't matter (which he claims is a myth, and it does matter) when resizing images for digital display (that is, on the screen, on the web, via a digital projector running off a laptop, whatever).

Firstly, for those that don't yet know, I want to explain the difference between DPI (dots per inch) and PPI (pixels per inch).

So let's start with PPI. PPI is a measurement of how a digital image relates in physical dimensions in a print. So, for example, if you had an image that was 1800x1200 pixels, and you wanted to print it at 300PPI, it would bring out to a 6"x4" image. If you suddenly told your computer to print that same 1800x1200 pixel image at 150PPI, then it would now be 12"x8" image. If you told it to print it at 600PPI, it would become 3"x2".

PPI is the masurement that you enter into Photoshop or whatever application in order to tell it how large you want the image to be when it comes time to actually print it out, and only when you want to print it out.

DPI, however, is measurement of the detail your printer can print and, as an aside, it's not always an accurate indicator of the quality of a particular printer.

For example, a CMYK dye-sublimation printer that prints at 300dpi, is going to be about the same level of detail and quality (unless you want to get really pedantic and technical) as a conventional CMYK ink jet printer that prints at about 1200dpi. This is basically down to the technology used. Dye-sub printers lay varying amounts of individual colour & black on top of each other in order to produce the final colour result. Ink-jet printers print coloured and black dots next to each other to achieve a similar result. So, for each "dot" on a dye-sub (remember, they all lay on top of each other), you would need four "dots" from an injket (one of each cyan, magenta, yellow and black). But, it does not change the physical dimensions of the printed image.

So, that out of the way, why does PPI matter when you're producing images for digital display, and not going to print? Well, in short, it doesn't.

When you resize an image from within Photoshop using specific pixel dimensions, regardless of what you set your PPI to, that image will always have those same pixel dimensions and filesize.

For example, here's an image of the lovely Raj that I shot last year. This was shot on the Nikon D300s, which has a native setting of 300PPI. So, after my usual post processing in Photoshop, here's the original 2848x4288 image scaled down to 200x301 pixels at 300PPI, along with a screenshot of the Photoshop dialogue box. This image file is 26.2KB.


So, let's have a look at the standard "give it to me at 72PPI" request.  The following image was, again, resized from the original 2848x4288 pixels to 200x301 pixels with a resolution of 72PPI.  This image file is also 26.2KB.



And finally, I did the test again, this time resizing the original 2848x4288 pixel image down to 200x301 pixels at a whopping 10,000PPI!  Oh yes, this file was also 26.2KB.


As you can see in the screenshots of the Photoshop dialogue boxes, when you're outputing specific pixel sizes, altering the PPI does absolutely nothing to the dimensions of the image, nor the filesize.  If you don't believe me, feel free to load up each of the three images into Photoshop and check the filesizes and PPI settings for yourself.

The observant amongst you will notice that the "Document Size" dimension are different in each of the dialogue boxes shown above, while the pixel dimensions remain the same.  This is due to the fact that Document size relates entirely to the image in its printed form (on paper!) not on screen.

The REALLY observant amongst you will also notice that the PPI "Resolution" input is in this "Document Size" section of the dialogue box too, and not in the "Pixel Dimensions" area.

PPI has absolutely zero effect when it comes to having specific pixel dimensions.  It ONLY relates to the size of the image when printed.

Feel free to comment below and tell me how I'm wrong.  I don't lock the comments on my blog posts just because some people might disagree or have evidence to disprove my statements. :)

Monday, 21 June 2010

Goodbye iPhone OS3, Hello iOS4!

So the day has finally arrived that my iPhone 3GS can look a little sexier for a few days before the iPhone 4 gets released.

The iOS4 update hit about 90 minutes ago, so obviously I was cool, calm and collected it and downloaded it immediately. :)

After a little initial bandwidth problem (it was stuck on "2 hours remaining" for about half an hour), I closed iTunes, restarted the download, and it took about 90 seconds.  Another five minutes to backup iPhone OS3, install and verify iOS4 and I'm now up and running.

Now for a pair of quick comparison screenshots : iPhone OS3 on the left, iOS4 on the right.


Obviously I don't have Apple's new Retina Display with the 3GS, but I am noticing that things seem to be displaying a little clearer than they did, perhaps due to new software to recalculate how resizing and font smoothing is done on the fly?

Not had much of a play so far, but the new "Folders" for organising the icons on your desktop into groups is looking rather nice. :)

Wednesday, 9 June 2010

D300s Replacement/Firmware wishes

After having read Philip Bloom's article Which Video DSLR to Buy, I've been having a bit more of a think about the video aspect of my D300s.

Please note that this article is based solely on the video capabilities (or lack thereof) of the D300s and while some of the features might be useful for stills photography too, that's not my focus here.

I've used the D300s alongside Sony EX1 and Z7 cameras for a few different projects now, and I've started to get a wishlist together of features it doesn't have that I personally feel are pretty essential.  Some (all?) of these could probably be implemented as simple Firmware updates, and perhaps one day Nikon will wake up and implement them, but some may require hardware updates in order to be able to maintain processing speed.

The first one for me is a biggy.  If no other feature were ever implemented, PLEASE Nikon, I beg of you, give us a live histogram on the liveview display.  If this were added, I could continue to deal with the fact that the D300s has no manual control other than the aperture.  At least with a live histogram I can zoom in on my Lastolite XpoBalance, let the camera meter, dial in some exposure compensation if necessary, then lock my exposure and know it's about right - I'd be a happy bunny, I'd be able to check via the histogram that my exposures are fairly consistent from shot to shot under different lighting conditions.  Without this feature, it's pretty much hit and miss, and I'm only taking the camera's word for it that it's metered my 18% grey consistently from one situation to the next (and if I exceed the limits of the auto-ISO in video mode, then I know it's going to be underexposed - even if I can't actually tell that until I get the footage back onto the computer).

Leading on slightly from this, given that I'm currently having to use the 18% grey section of the XpoBalance to get the D300s to produce a (relatively) consistent exposure between shots, please let me spot meter in video mode.  Being stuck in matrix metering mode means that I have to take my camera off the tripod, zoom in completely to my grey card so that it fills the screen, lock the exposure, and then move my camera back to its original position.  Not a huge pain in the arse, but a pain none the less.  Being able to spot meter an 18% grey card that's only taking up about 1/8th of my shot would be lovely, thank you.

Then there are the obvious ones.  Only 24p?  Come on now, not all of us live in the film world.  Having to transcode 24p into 25p to burn out to DVDs is a step in my workflow that I'd rather not have to be honest with you.  It never turns out as well as it would have if I simply had the option to record 25p in the first place, and trying to composite 24p footage with 25p motion graphics in a 25p composition in AfterEffects is just a nightmare.  Please give us other framerates.  25p would be awesome and, to be fair to the Americans, let them have 29.976 too (my wife is American, so it'd be great if I could record 29.976 footage, and not have to run 24p footage through Twixtor or something to be able to mail her family a DVD).  50p and 60p are other obvious framerates that many of Nikon's competitors at similar and lower price points can already achieve,

720p.  Ok, for some this one is massive.  For me, it's not such a big deal (although it may become one by the time the D300s & D3s are replaced in Nikon's lineup).  The vast majority of my projects for clients still end up on a PAL format progressive mode DVD, which are standard def.  As such, shooting and editing in 720p and then scaling the final project down to 720x576 with a 1.42 pixel aspect ratio is not a huge issue.  But, the future is just around the corner.  Blu-Ray is actually getting affordable to the general population, even Youtube now supports 1080p high definition video file uploads, and monitors that are capable of 1920x1080 resolution are becoming increasingly more available in the local computer stores.  It also means that even if I am still ending up with a DVD project, scaling down from 1080p instead of 720p will still provide a better end result.

Finally, please give us full manual control.  Canon have several bodies at a similar or lesser price point than the D300s that offer full control over the aperture, shutter speed and ISO.  Why can the D300s not do the same?  Why has this not already been fixed in a firmware update?

Edit : Maybe not "finally".  I know there was something else, but off the top of my head I don't recall quite what it was. :)

I know that the D3s does overcome some of these inadequacies in the D300s (live histogram and full manual control, for example), but I shouldn't have to go out and spend almost three times the price to be able to get these two minor, but essential, features, especially when the D3s still only records 720p.

At the moment, I'm debating my video future.

Do I continue to struggle with the D300s as merely a support camera for the EX1 with which I normally shoot?

Should I forget shooting on a DSLR entirely for now and just get the Letus Ultimate 35mm adapter so I can put my Nikon glass on the EX1?

Should I hold out and see what Nikon have to offer in the inevitable D400/D4 bodies?

Or do I just pick up a 5DMk2 & Nikon lens to EOS mount adapter and be done with it?

I'm thinking I'll just wait until the D400/D4 are released and see what they offer, but if Nikon can give me a D400 with 1080p, 24/25/30fps, full manual control and a live histogram, I'll take 2 please - if not, I'll probably be in the market for a couple of second hand 5DMk2 bodies and lens adapters.

Saturday, 5 June 2010

Online video streaming via iPhone?

After watching a few live streams over the past few weeks from Chase Jarvis, Philip Bloom and Chris Jones, I decided to do a little bit of research into what's currently available for online video streaming on the cheap.

In the past, several years ago, I'd used Microsoft's Windows Media Encoder, which was great for the intended uses at the time, as I knew all the end users watching the stream were running Windows.  I could send out desktop captures, webcam feeds, live input from capture cards, or even saved pre-recorded videos that were already on my PC, and I could switch between them at will with a playlist.

Now, my intentions have changed, as have the capabilities of the audience.  As well as the various non-Windows desktop operating systems out there (MacOS, Linux, etc), there are also mobile devices such as the iPhone, iPad, Android, etc., so sending out as a Windows Media stream is no longer really a viable option and nor is a Flash-only option if I want to keep iPhone and iPad visitors happy.

My initial goal was simply to find somewhere that I could stream live and recorded video at little-to-no cost that would be viewable on the iPhone.  I hadn't really considered recording videos or streaming out from the iPhone, but it turns out I can do that to (hence this little blog post).

I've been taking a very close look at Ustream (as well as TwitCasting, but we'll get on to that later).  Ustream has three different applications available via the iTunes store that can be used on the iPhone, iPod Touch and iPad in order to be able to utilise various features of the site.
The Ustream Viewer should (I'm assuming) work on any version of the iPhone, iPod Touch or iPad (if you know different, please post in the comments).  It essentially allows you to view any live or pre-recorded feed full screen on your device, as well as search.

The Ustream Recorder lets you use your iPhone's camera (3GS only according to the info) in order to record video to your phone.  Nothing new here, you can do that with the 3GS anyway, but it also allows you to review and manage your local and remote (on Ustream) videos, set tags and schedule uploads.

It will also allow you to import and upload videos previously recorded using the iPhone 3GS's default video recording application.  You are also given the ability to upload to Youtube or Facebook and automatically post a tweet when the upload is complete.

Finally we get to the Ustream Live Broadcaster.  Firing this up immediately presents you with a box asking whether you want to run in "Local" or "Live" mode.

Running in Local mode is not that much different to using the Ustream Recorder, except slightly more limited.  Using the Recorder, you can touch the screen in order to select your focus & exposure point as you can when shooting stills normally with the iPhone;  Using Live Broadcaster, you can't.

Running in Live mode, however, is very nice.  It automatically (depending on your options) logs you into UStream, selects the channel, turns on your camera and gives you buttons to manage your remove and local videos, change your options, or start broadcasting.

Once broadcasting, you can start or stop a poll on the fly, mute or unmute your audio, send out a post to twitter (presumably announcing your feed), or stop the recording.  A little status section at the top tells you for how long you've been broadcasting, and how many viewers are currently watching your feed.

It takes a minute for your feed to properly kick into action once you've got it started up, but once it's up and running, it happily chugs away with about 15 seconds of lag (my iPhone is connected to the net via WiFi, experiences and speeds will obviously vary depending on your iPhone's connection).

Upon completion of your stream, you are asked if you wish to save and announce the stream to Ustream, Facebook, Youtube and/or Twitter.

That's pretty much it.  I don't plan on doing a whole lot of streaming from my iPhone out to the rest of the world, perhaps a few minutes here and there, but it's nice to know the ability's there if I ever need it.  Now just to see how well it all works from the PC.

I also mentioned TwitCasting earlier.  This is quite a neat little streaming app, which embeds your twitter feed below the video you're sending out.  Not quite as useful as the Ustream applications, but something cool to play with if you just want to make some quick little video segments to post on Twitter.  It will also allow you to save and store your recordings, although it won't allow you to stream/upload previously recorded videos.

Edit : I will be popping images up for this article within the next few days.

Tuesday, 1 June 2010

Updated : What's in the bag?

In my previous "What's in the bag?" post, I listed the equipment that I would usually take out with me when going off to shoot.  Since then, things have changed a little bit; I've picked up a few more bits and pieces and I now have far more equipment than I can easily carry on the train I often use to get to various locations throughout the country.

So, my bag packing styles have changed (and I now have four bags from which to choose the most suitable for a given job).  Which bag(s) I use, and what goes into them now varies from job to job, and I will be showing you some of that equipment over the coming weeks, along with some information on why I chose particular items.

If I can't justify why something should be in my bags, I shouldn't be taking it with me!

First off I will be starting with my new camera backpack, the Lowepro Slingshot 300 AW; A much smaller, lighter and more convenient solution than the Cyberpack 6 for those less demanding tasks, such as shooting recon pics and mockups with a friend or assistant while scouting locations.  Handy for the occasional day out at the zoo with my wife too. :)

It may be a small bag, but it can still fit two bodies (with grips), 3 or 4 lenses, an SB-900 flash and a couple of extra bits and pieces.  So, stay tuned.

Friday, 28 May 2010

Blogging vs. Real-Life Part 2

I seem to be failing miserably at all this blogging business these days, but it has unfortunately had to take a back seat to the real world for a little bit longer than I had planned.

For those that were curious, shooting with Dirk Benedict at the Who Store went great, and he's a thoroughly nice chap (when he's not reading reviews of the new "A-Team" movie, or somebody reminds him of the fact that Starbuck's female in the new "Battlestar Galactica").  I must remember to bring along a bottle of Glenmorangie if I ever have the opportunity to meet him again.

I should be back again there next month to shoot the 7'1" monster (and I say that in the nicest possible way) that is Ian Whyte.  For those of you who don't know, Ian was the predator  (hence the "monster" reference) in the two Alien vs. Predator movies and, oddly enough, a double for Madame Olympe Maxime in "Harry Potter and the Goblet of Fire".  Currently featuring in the new remake of the film "Clash of the Titans" as Shiek Sulieman.

I'm not going to end this post as I did my last one, seeing that I charged all my batteries last night for this weekend's frivolity at the Yorkshire Game Fair, but I will certainly make an effort to try to keep things a bit more updated when I get back.

I've had a lot of ideas for posts and articles that I really want to get on here; Not only to help you lot out, but also so that 6 months down the line I can remember it myself. :)