Anyone ever used a Digital Laser Rangefinder to help focusing?

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Will
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I noticed that amazon's deal of the day is this Bosch Digital Laser Rangefinder and it got me wondering if this would be useful for photography, so I wanted to know if anyone's ever tried to use one? If I ever bought one it's main use would be DIY, but will it pull double duty and be useful for photography?

The situation: You're out landscaping and know what you want in your shot, so you use a hyperfocal calculator to work out you need to focus 8.5m into the scene, but where the hell is that? Unless you're super good at estimating distance this is going to tell you quickly and accurately, which is helpful.

My questions are:
1. Do these work well outdoors in strong sunlight, because the reflected laser light might get swamped out?
2. If you've got something nice (like a building or car) to reflect off then it's easy, but how well does it work if you're point at something less nice (like grass or leaves)?
3. In very dark conditions would it actually help achieve focus because you could point a red dot in the scene for the AF/you to use?

Notes:
- This one only has a max distance of 15m, which might be limiting, but this highly rated Leica one would be a more expensive alternative (max 80m).
- I realise you could use other techniques to get accurate focusing (eg live view), but I'm curios about use these things.

Will
 
Hmmm.... how many lenses these days have 'accurate' distance markings on them?

You set your HF distance then just make sure your subject is at that point. How to tell it's in focus? Look in the viewfinder :)

Stick to measuring rooms!
 
Seen the Leica Disto recommended and used quite frequently for medium and large format photography.
 
Interesting idea, but unnecessary IMO.
When judging HFD just guess a little long. When you focus beyond the HFD you loose *a little* DOF up close, but the near point never goes beyond the HFD. If you focus short of the HFD you gain *a little* DOF up close, but you loose *a lot* of DOF in the distance.

Choosing an optimal FL and aperture for the hyperfocus/scene would be more important IMO.
 
Oh, and there's little need for an HFD calculator/app. Just remember f/16 for APS or f/11 for FF. At that aperture the HFD is roughly the FL as a percentage of the FL (in ft). I.e. 50% of 50= 25ft for a 50mm. 30% of 30= 9ft for 30mm, 10% of 10= 1ft for 10mm. It's close enough but the Canon APS 1.6/1.7 crop factor is a little more "off."
You can also just move the decimal place left one and square the FL (i.e. 5x5=25 for 50mm) if you find that easier.

Since the idea is for DOF balanced against sharpness/diffraction there shouldn't be much reason to use any other aperture for most cameras. But if you change the aperture number by 2 (2x, 1/2) you also change the HFD by 2. (i.e. APS @ f/8 would be 2ft for 10mm).
 
I have an ancient Voigtlander shoe fit rangefinder. It is accurate enough for standard and wide angle lens, but no rangefinder is accurate over long distances with a tele lens.

There is always a margin of error that increases with distance.

An old WW2 artillery rangefinder would be accurate to 20 or so yards at a mile (say 1%). But then the variation of the probability, for shells and guns would be more than that.
 
Didn't realise those laser jobbies were so affordable. Might get one for the toolkit, but not for focusing. The problem is transferring values accurately to the lens - no chance of that.

Also, hyperfocal distance focusing is really easy. It doesn't require absolute accuracy and you only have to estimate distances of 2-3m max with wide-angles. HFD technique is not practical with longer focal lengths/distances, unless you want to shoot at f/90.
 
Since the days of high pixel density LCDs and magnified live view I know it's not the best solution, but I was curious if anyone had tried (perhaps back in the day). It sounds like the only potential benefit would be during night photography where a little red dot would help focus on a very dark object, but el cheapo £1 laser keyring would do that just as well.

For £30 it's probably well worth it for DIY, and who knows, maybe I'll find a photography use for it one day. Any ideas welcome....
 
The old mans got a proper one for bunny shooting, about £100. Because we use air rifles you have to be close 30-50yds can be a smaller distance than it looks. I haven't got one so just guess. I did think about it for photography but unless there's anything of interest to focus on I just go for a third from the bottom, eg seascapes.
 
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