Kite Aerial Photography
When I choose my 5Mpixel camera for RIG04 at the end of 2003 I did an extensive survey of all the main manufacturers of high-end compact cameras. I have not reproduced this here because this information ages so quickly. Rather I present here a list of areas that you should consider when selecting a KAP Camera.
This was done specifically with 180 to 250g Compact Digital Cameras with 4 to 6 Mbyte CCD sensors, although I'm sure the headings and considerations may help with the selection of other KAP cameras, digital and film.
A good place to start is by looking at what experienced KAPers fly, they have been this way recently, and have experience on their side, although I'm not the most experienced I hope this page will give you some insight into what's important and what's not.
When you make your choice you can get some of the data required from the web, there are numerous sites that allow you to list and compare cameras. However some of the information you need is harder to obtain and I found myself downloading Camera Manuals from manufacturers web-sites to get this greater detail. Finally, even the manual didn't answer some of the questions, and I resorted to trying the camera out in shops, asking others with similar models, e-mailing other KAPers, and asking questions on the KAP discussion page.
Light, Camera, Action!
First you need to consider where you are - always a good place to start!
So, pick your price and try to get the lightest, best camera deal you can. Sounds simple, but before buying read on - there are a few other recommendations in my opinion!
An interesting article I read recently (assuming I drew the right conclusions :-) suggested that for Compact Cameras, then 5 to 6Mpixel was as high a resolution as you could get before the quality of the small lenses used in these cameras became the picture quality limiting factor.
One other cost consideration is memory cards (or film - some people use medium format and still use film!). Different film and memory cards all have an associated cost, which can be significant with respect to the cost of the camera. There is no point having to keep raising and lowering the rig to put in more film or change memory cards. For digital cameras I would recommend having at least 100 shots available per memory card, and if possible 2 cards.
Most Digital Cameras allow a choice of image compression, and hence quality. This is inextricably linked with the memory size. For a given memory you get more images with higher compression, however the quality of the image suffers, another choice...
I consider it essential that the camera has Aperture Priority, this allows you to fix the aperture at maximum (minimum f setting) and force the shutter speed as high as it will go. This will greatly improve the number of images that are critically sharp.
Most compact cameras in AUTO mode do not behave like this. They tend to use a low f stop until the shutter reaches about 1/125, and camera shake is less of a problem, then they increase the f stop to get more depth of focus. Depth of focus is not worthwhile in KAP because you should always be at least a few meters away from the subject! This need to force the shutter speed up will be a recurring theme, and does beg one other difficult to answer question...
For KAP, I would recommend shutter speeds in excess of 1/500s. Once here it wont take much more light to get you to 1/1000, which is the maximum shutter for some cameras. When the camera reaches this point it could either:
With KAP, and the camera remote from you, option 1 is not what you want, an over exposed picture is better than none at all. This is the kind of information the manual doesn't tell you, and I have resorted to trying the camera in a shop and taking close up pictures of light bulbs to see what happens!
You should be able to lock the camera on infinity.
You may even consider cameras with no automatic focus at all, although for compact digitals, you tend to get this feature whether you want it or not.
For all the same reasons as for FOCUS, you don't need flash.
The camera should have a means of deliberately under or over exposing the shot with respect to what it's automatic settings tell it.
I usually have this set to 0.3 or 0.7 stops under exposed. Often my subject matter tends to be bold, i.e. a white lighthouse tower, and the cameras automatic exposure in trying to find a compromise over exposes the tower. Most cameras have more precise ways of dealing with this - e.g. changing the exposure area, or using a half press of the shutter. These aren't really practical for KAP, so I go for the underexpose everything option. If necessary this limited amount of under exposure can normally be recovered in a photo editing package later.
A useful side effect however of doing this is that it will push the shutter speed up a little, which is always good in my opinion!
With a film camera you choose the film speed, with higher specified Digital Cameras you can set the speed, or rather the gain of the CCD sensor. Normally the settings vary from around 64 to 400ASA equivalent, with an automatic mode. AUTO normally means the camera uses the slowest setting until forced to use higher settings in poor light, this also increases the amount of noise from the CCD sensor.
I set the camera to the second slowest setting (100 instead of 64, 200 or 400 in my particular case), this gives a little extra gain, to allow increased shutter speed, but isn't so sensitive as to allow the CCD sensor noise to become a problem.
Perhaps not essential but a USER or MY MODE is very useful. It allows you to store settings in a camera for quick recall. When you launch the kite and set-up the rig you have lots of things to do, this feature greatly simplifies the set-up of the camera, so things don't get forgotten in the chaos of launch.
Battery and Power
Are you going to run the rig from one battery or have separate batteries for the servos, camera, video downlink etc? Sharing saves weight, but makes rig design more complex as the different parts tend to require different voltages.
Another consideration is that some cameras behave differently when powered from their battery and from the external power connector. Often in the latter case the power saving features are disabled, so the camera uses more power anyway.
If you are going to power the camera from it's own batteries, standard batteries (i.e. AA type) are best. Invariably they have a good power to weight ratio (especially the new NiMH cells), and they can be easily replaced with stand-by alkaline cells in an emergency. If your camera uses a proprietary battery pack - make sure it's charged, or you have a spare!
Digital Camera especially are power hungry. There will be times when you fly when you are walking about and looking for a shot, during these times you want the camera to be in sleep mode, using as little power as possible. Being able to vary this time is useful, too short a time is annoying, too long wastes batteries. When in this mode you need to be able to wake-up the camera, preferably with the shutter control, some cameras you need to press the ON/OFF button to wake it up, this will add weight and extra complexity if you need to control this button remotely.
If at all possible you should consider releasing the shutter electrically or with infra-red (IR). This reduces the mechanical complexity and the weight of the rig. It also makes it easier to load the camera into the rig in the field.
Cameras from the late 1990's had serial ports which could be used to control the camera, but more recent models in the early 2000's have moved to USB, which is much more difficult to implement control with. Maybe the next wave of digitals will have better remote control functionality that KAP could take advantage of?
There is a big difference between cameras in the time between pressing the shutter and the picture being taken, this can be especially frustrating with a constantly moving KAP suspension. Although some of the things already mentioned will help reduce this (e.g. fixed focus reduces the work the camera has to do in preparing to take the picture), I'd recommend you choose a camera with as short a shutter-to-picture time as possible.
If considering IR release, make sure that you are happy with how this works as some makes only allow a delayed release (for self portraits) rather than an instant release. Additionally you need to look and see if the camera is woken from sleep mode by the IR signal if you are interested in conserving batteries as discussed above.
There are various schools of thought about a video downlink of the viewfinder. Whilst digital cameras without video outputs are generally smaller and lighter, you should carefully consider whether you should have a video output on your list of wants even if you don't plan to use it initially, or feel it's unnecessary.
Whilst on this subject another couple of points about the video output. Make sure that the LCD display can be manually disabled or disables automatically when the video connector is plugged in. The LCD monitor is one of the most power-hungry parts of a digital camera, and you don't need it when flying! This was another feature that was tested in a local camera shop. After engaging the assistant, I produced a pocket TV and used the video lead that came with the camera to see what happened when the video output was used!
Finally most cameras show a freeze-frame of the picture you have just taken - but some do not! This is an excellent feature for KAP. Because the camera is remote from you it is good positive feedback that a picture was taken, and your rig is working properly.
Finally a few ideas that you may consider, but are not easily obtainable with today's digital cameras:
That's a lot of information, I hope you found it useful. As with all cameras there is an element of personal choice, and dependency on your other requirements - have fun choosing your camera! Thanks to Peter Bults for his critique of this page from his experience.