All 23 entries tagged Photography

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August 19, 2005

Technology moves very quickly

Writing about web page http://www.dpreview.com/news/0508/05081902kmz6.asp

The Konica Minolta Z5 was announced in January and I bought mine in February, but already they've announced its successor, unsurprisingly called the Z6, due to be available next month. Fortunately it isn't hugely different from the Z5, 6MP instead of 5 and better battery life but otherwise prety much the same, so I'm not bothered by this.

But if you had the Z5 on your shopping list you might want to wait for the Z6 to come along…


July 12, 2005

Autostitch isn't perfect…

Autostitch has done a pretty spectacular job of stitching together everything I've thrown at it. Probably at least as good as I could manage by hand (before my patience ran out, that is). Until yesterday…

While out cycling yesterday evening I came across a really nice sunset. All I had with me was my camera phone, but I thought I'd take it anyway. I took the scene in four pieces, with lots of overlap, and threw them at autostitch when I got home. This was the result:

I thought nothing more of it until this afternoon, when it occured to me that this wasn't actually wide enough. I thought I'd taken more of the scene to the left. When I checked this evening, it turns out I had. Autostitch had only pasted together two of the pieces. What happened to the others?

Well, because I was using a phone camera, everything was on auto. The exposures were different enough for autostitch to be unable to match them. Havng the sun in the right-most piece had made the sky and foreground fairly dark. As I panned left, away from the sun, the auto exposure lightened everythig up. Putting in a bit of effort by hand, starting first by adjusting the levels to match the exposures more closely, making each piece progressively darker to the left, followed by a bit of blending at the seams, produces the image I was expecting to get from autostitch in the first place:

You can still see the joins, so obviously I need some more practice at blending the pieces together, but it isn't too bad. For the record the auto panorama function in Photoshop Elements did a terrible job – it really didn't like the mismatched exposures.

This just reinforces one of the rules for making good panoramas – where possible set the camera to manual exposure to get the same exposure for each piece.


July 11, 2005

Camera phones are getting better

Follow-up to What a nice day from Steve's blog

A few months ago I took this shot of the sun reflecting from a University House window. It was taken with the camera in my phone, a Nokia 6230, because that was all I had on me at the time.

I've got a new phone now, a Sony Ericsson K750i, so I thought I'd try and repeat the shot to see how it compares to the old one. Of course, the sun is much higher now, so the reflections are in different places and I can't take exactly the same shot. The orignal and today's are below, Nokia on the left, Sony Ericsson on the right.

There is an obvious difference in the images at this size, but the difference is even more obvious if you look at the full-sized images (just click on the ones above). The Sony Ericsson had a 2MP camera, compared to the Nokia's 0.3MP one, which explains it all, probably. With the large difference in resolution it is hard to say if there's any difference in quality. One of the other differences is that the lens on the new camera isn't as scratched as the old one, so there's a much reduced starburst effect. And it will stay that way because this one has a lens cover:-)

This phone might just be good enough to be my "take anywhere" camera, when I can't be bothered to take my proper camera, or didn't expect to need it. Which is perfect because I rarely go anywhere without my phone…


June 30, 2005

Panoramic photos


This panorama (full resolution version) in my blog about the Gala Concert has caused a few people to ask about how it was produced. Basically it was put together from 7 or 8 individual shots, deliberately taken so that they overlap. I usually try to make the pictures overlap by at least 25% – up to a point, the more overlap the better.

Then I used autostitch to glue them together. Autostitch does what it says on the tin. Give it a collection of overlapping photos and it works out for itself which order they go in and how to paste them together. It doesn't do a perfect job. If you look at the top right of the Maths building, and especially the top right of Riley Court, you'll see some ghosting where the join isn't perfect (you'll need to look at the high resolution version to see this). But the end result is still pretty impressive for a fully automatic process, and touching up those imperfections is straightforward (so, why haven't I done it you ask:-)

I have another example produced with autostitch, taken of the National Mall in Washington DC from the tower at the top of the Old Post Office:

There's pano stitching functionality in Photoshop and Elements also. I haven't tried that yet. Does anybody know how good a job that does?

When setting out to deliberately take pictures for stiching together, there are some things to bear in mind:

  • Ideally you should pivot the camera around the optical centre of the lens. That's kind of hard to do, especially when you've got a zoom lens. The closest you can easily get is to use a tripod. As it happens, the Gala pano was not taken with the help of a tripod, so decent results are possible without. The Washington panorama was also taken hand-held.
  • Overlap the individual pieces by at least 25–30%.
  • If possible, use a manual exposure so that all the pieces of the pano have the same exposure.
  • If possible use manual focus to keep the focus consistent across the whole panorama.
  • Be careful of moving objects, or they might end up appearing more than once in the finished result!

When thinking about panoramas, I always used the think of mountains and open spaces as the major subjects, but this gala panorama has made me realise than the technique is more widely applicable. I'll be looking for other unusual opportunities to use it.

One thing I'd like to try sometime is to do a small scale version of the 2.5 Gigapixel photo, by stitching not just horizontally but also vertically, to create a very high resolution picture. I don't think I'll make 2GP, though! I just need to find a suitable subject…


May 22, 2005

Polarising filters

I've just acquired the ability to use an old Cokin polarising filter (originally bought for the 35mm SLR I had before the one I've just replaced with a compact digital) with the new camera, and I'm rediscovering how useful it can be. It can help enourmously to cut down reflections when taking pictures involving water or glass, but it can also make a huge difference to skies. Just look at these two:

The one of the left was taken without the polarising filter. The one on the right was taken about 30 seconds later, so basically with exactly the same lightinh conditions, but with the polarising filter fitted and rotated for maximum effect. Just look how much different it has made both to the colour of the sky and to the lighting of the clouds. Much more dramatic.


May 12, 2005

Blurring with Photoshop

Follow-up to Bluebells, at last… from Steve's blog

Of the images in the referenced entry, Max liked the effect in the one bottom right where the flowers in the background are out of focus but still recognisable, comparing it to a similar image of his.

I agree, but for me there's a difference between the two. In Max's image the background does not overlap the forground to the same extent as mine. I find the background in mine just a little too distracting. If I could take the shot again I would use a larger aperture to throw it a bit more out of focus. But, maybe photoshop can help?

By carefully selecting just the foreground flower and then inverting the selection, it is possible to apply a bluring filter just to the background. I found the "Blur" and "Blur more" filters didn't do as much as I'd hoped, so I moved on to the "Gausian blur" filter. This has one setting, a "radius". I'm not completely sure what it means, but I guess there's some averaging of pixels going on, and the radius setting determines how many pixels are averaged together, and therefore determines the extent of the effect. I tried settings of 10, 15, 20 and 25 applied to the original image. All are reproduced below, original first and increasing in bluriness to the right (click on the images to get a larger version):

To maintain the "blurred but recognisable" effect, I think that a radius of 15 (the middle one above) is as far as you can take it, but I quite like the rightmost one (radius 25). I'm quite pleased that the effect is pretty realistic, with the background really looking like it was originally out of focus. A useful technique when you forget to use, or can't use, a small emough aperture to get the effect you need.


May 11, 2005

Bluebells, at last…

So I finally got to Tocil Woods today. The bluebells are wonderful, and there are a lot of them! It is really hard to capture just how numerous and blue they really are. No doubt Photoshop could go some way to improving the effect, but for now here are today's attempts untouched:

The colour in the rightmost one came out about right. And a couple of close-ups, just 'cos I like close-ups:


May 09, 2005

Close–ups

Writing about web page /maxhammond/entry/bluebells/

Writing about an entry you don't have permission to view

For various reasons, I still haven't managed to get to a bluebell wood. I have one just across the road from my house, as well as working close to Tocil, and due to being away, having too much to do and the weather, I haven't yet managed to get to either of them.

However, during a recent free few minutes I decided to have a play with close-ups on the bluebells in my garden. I found the focussing really difficult, no doubt not helped by trying to do it in a hurry. Many of the shots looked like this, with the wrong bit in focus:

Ironically, the best shot (in terms of focus anyway:-) was taken using auto-focus:

I need to get to Tocil wood one lunchtime, before all the bluebells disappear…


April 11, 2005

Travelling with a digital camera

A little while ago I invested in a new digital camera, my first, a Konica Minolta Z5. The main reason (excuse) for buying this was an upcoming trip to Washington D.C. from which I have just returned. I deliberately bought the camera a while ago to give me a chance to get used to it, but still, the first time you take something like this on a major trip is always a learning experience.

One thing I was concerned about was battery life. I had deliberately chosen a camera that will run on AA batteries so I didn't have to lug a charger about (particularly thinking about holidays I take where I don't have easy access to mains power). I have two sets of rechargeable AA batteries (2500mAh NiMH) that I normally run the camera on. In my previous playing about I was usually lucky to get 70 shots from a set, so I took a couple of spare sets of Duracells too, expecting to need them. It seems the poor battery life was due to my excessive playing with things, because I took about 370 shots while away and didn't quite use up the two sets of rechargeables. Didn't need the Duracells at all. Still, they were a nice comfort blanket.

One thing I was less concerned about was storage space for pictures. If I'd taken a film camera I would probably have got through only 3–4 rolls of film on a trip like this – maybe 150 shots at most. I had enough storage for 200, and was expecting to be able to delete the rubbish as I went. As it turns out I took more than double what I was expecting – enough to fill my available storage twice over. That would obviously have been a problem except that, for unconnected reasons, I had a laptop with me (for the purpose of entertaining the kids, not as a digital camera support device). So, I was able to download stuff to the laptop. In future, though, I think I'll need to take more storage with me. Fortunately, SD cards are cheap…

Once I had downloaded the pictures to the laptop (and obviously deleted them from the camera), I had to think about what to do with them. It would be a shame if the laptop got dropped or otherwise damaged in transit and I couldn't get at its contents, so I took some blank CDs with me and wrote the photos to them as soon as I had extracted them from the camera. My plan was to have two copies, one for hand luggage and one for hold luggage, just in case. I also took CD-Rs and CD-RWs, planning to have a copy in each format, again just in case. Paranoid, me?

As it turns out, both of the CD-Rs I had failed to write when I tried them. It is unlikely I picked up two dodgy ones when I packed. Could they have been damaged by the X-ray machine (they were in the checked in bags)? So, I was left with CD-RWs, which did work, but I only had enough space for one copy of everything. When I burned them, I verified the files immediately afterwards, and all was fine. These travelled in the hold on the way back, and did not read completely afterwards. Most of the images read OK, but some did not. X-rays again?

The copies of everything on the laptop, which was of course in my hand luggage, survived intact so I didn't lose anything. But this now makes me nervous. What is the best way of making sure you don't lose digital photos while travelling? I won't be putting CDs in hold luggage again, but that does leave me in the position of having all copies of my pictures in one place.

If I'm somewhere with an Internet connection I could upload all my images to somewhere convenient, but with almost 1GB of the stuff, that could take a while. And where would I put them? I suppose there's always gmail…:-)


March 20, 2005

Learning Photoshop

I've done a small amount of playing about with Photoshop and similar tools in the past (mostly PainShop Pro, in fact), but never really made an attempt at fully exploring its capabilities, not least because I didn't have a source of lots of digital images. Until now. So, alongside teaching myself how to take photographs again, after a bit of a break from serious photography, I'm trying to learn the inner secrets of Photoshopping (is "Photoshop" a verb yet?) To this end, I've started reading "Digital Photo" magazine, which was recommended by several people in rec.photo.digital. April's issue (why do they do that – produce April's issue in March?) described some interesting techniques and came with a CD containing screecams of them being used, along with an audio commentary to explain what's going on.

To force myself to learn this stuff I'm planning on taking some of my images each month and trying out some of the techniques from the magazine. Otherwise, I'll just read the descriptions, think, "That's clever", and forget how they work by the time I actually need them. This month's first experiment was with the image to the right. It was taken in Scotland, ealyish in the morning, with my phone. So, not a great quality image technically, but it perfectly suited the techniques I wanted to try out.

What's wrong with it? Well, it is a bit boring. Or maybe a lot boring. Very flat and with nothing much of interest.

Technique number 1 is to simulate graduated filters. I've used blue and neutral (i.e. grey) graduated filters with film cameras before. These are square, and are a solid colour at one end and fade to transparent at the other. They are used to add colour to a sky, or to avoid overexposing a part of the picture. You simulate them in Photoshop by creating a new layer with blend mode "Multiply" and using the "gradient tool" to create the filter. You'll probably want to fiddle with the lightness and saturation of the layer to get the desired result. You can also change the opacity of the layers to lessen the effect.

Technique number two is to adjust the lighting and contrast of selected areas of the picture, using a selection with a large "feather" to ensure the adjustments blend seamlessly with the unadjusted picture.

So, to this picture I added a blue gradient to put some colour in the sky and an orange graient to warm up the horizon and the mountains (there's actually a hint of orange in the existing clouds, which is what gave me the idea). The orange gradient is actually at 45 degrees, so that there's more orange on the right than the left. Then the water was lightened a bit and made more contrasty using the levels tool, and the fields were lightened in the same way (it is surprising what you can find in apparently very dark areas of digital photos). The final result is on the left. I'm quite pleased with that for my first real attempt at proper "digital darkroom" work. And hopefully, after having played with these techniques a little bit I'll remember them better when I really need them.

(Click on the pictures to get to full sized version in the gallery.)


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