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Our photography club is looking to purchase a new project with a budget of £2000 to £2500 GBP. It's a bit of a minefield.

Photo forums recommend the Canon SX80 Mark II, which has a native resolution of 1400x1050. However, for a little more I've come across the Epson EB-G5450WU which has a native resolution of 1900x1200. The contrast ratio of the Epson is 1000 : 1, and the contrast ratio of the Canon is 900:1?

I am not entirely sure what contrast ratio means and if it has much of a bearing on displaying photographs.

We'll only get one go at choosing the correct projector for our club. Any recommendations, help in this area and pitfalls to avoid will be most welcome.

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Contrast ratio is the ratio of intensity between the darkest point the display can make and the brightest. In a dark room, the bright white spot will be 1000 times brighter than the blackest pixel on the 1000:1 ratio or 900 times on the 900:1. From that stat alone, the Epson has an advantage, however that also isn't the only stat you need to look at.

Maximum brightness (Lumen output for projectors) is also critically important. It is quite typical for brighter projectors to have a lower contrast ratio since preventing light leakage becomes harder as brightness increases. The lumen output of a projector determines how bright an image can appear and what kind of brightness the projector could be used in.

For example, if the Epson was a 1000 lumen projector and the Canon was 5000 lumen (hypothetical, I'm not looking at their stats), then while the Epson may win in a dark room, in a well lit room, the Canon's brightest pixels would be much brighter than the pixels lit by ambient light and thus the effective contrast ratio for the Canon would be higher in a well lit room since it would stand out more from the ambient light level.

There is also a question of the color accuracy of the projectors which is difficult to measure from most stat sheets. Color accuracy is a trick with projectors in general since ambient light impacts them so strongly, but just like other types of displays, not all projectors are created equally in relation to how well they can reproduce color.

So to sum it up, the main things you want to consider when looking for a projector for photography are generally going to be the contrast ratio for the condition you will be using it in, the ability to reproduce color well and then finally the resolution of the projector.

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From my experience of buying and operating similar projectors for a camera club in the past I'd start out by saying the factors and figures you need to consider are not the ones they usually sell projectors on, and certainly applying bigger=better may not be appropriate...

Pitfalls

Most projectors are not sold or built for displaying photos, video is often forgiving of a poor display.

Try not to listen to the herd too much. Around the time I was last purchasing the photographers who were highly respected on the club scene (PAGB affiliated bodies) made some very poor recommendations to other clubs who have since had to replace their equipment.

Light output

Light (lumens) output is a relatively useless number when you're looking at a device which is primarily going to be used in the dark, even a low output device in that price range will be beyond adequate in those conditions (the SX60 I've used has to be dialled back heavily to avoid blinding the audience.)

Contrast ratio

Again the assumption bigger is better does not apply when what you want is to express a range of tones in a darkened room. 500:1 is more than ample, bearing in mind you're probably only giving it 8bpc anyway so only have 256 tones per channel.

Resolution

1900x1200 seems like the better bet on paper but the practical advantage is limited since if you want to use the full resolution then you are either giving a huge advantage to the display of landscape/letterbox images or limiting the output to the projection screen. The latter has the disadvantage that leaked light will be visible off the screen area and be very distracting in a competition/critique session (a lot may depend on your venue) and limiting relies on software support, which you won't have if it's garbage like FilmFreeProjection (which is unfortunately popular.)

So, what do I look for?

Ultimately you need to get the right type of display technology because that's what will determine the quality of your tonal range. LCOS is probably the best I've seen and after that LCD. Definitely avoid DLP since it has very little tonal range (and very vivid primaries).

Beyond that the proof of the pudding is in the eating and if you can find nearby clubs which have the projectors you're considering you may be able to get their owners to bring them over (or you could take a deposition and go visit them on a digital competition night.)

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