Hyperfocal Distance using 50D and EF-S 18-200mm 1:3.5-5.6 IS

[sauron]

Hi all , this is my first thread on this forum.

Recently i brought a 50D with a 18-200 lens. I just wanted to take images from hyper focal distance. But I have some doubts about the lens

1. EF-s 18-200 doesn’t have a distance scale or a DOF scale on it. So only possible way to calculate the hyper focal distance is using a hyper focal distance calculator or a table. But it is really difficult in a practical scenario since the distance has to be measured manually. Even there could be impossible situations where you can’t measure the distance in the field. So is there any other way to take photos from its hyper focal distance using mentioned camera and the lens?
2. When taking a photo from its hyper focal distance should the focusing mode always be manual?

Thank you.

[Donald]

Sauron

Well done on putting up your first post. The first one is always the most difficult, as you wonder what other people will think about your question.

EF-s 18-200 doesn’t have a distance scale or a DOF scale on it. So only possible way to calculate the hyper focal distance is using a hyper focal distance calculator or a table. But it is really difficult in a practical scenario since the distance has to be measured manually. Even there could be impossible situations where you can’t measure the distance. So is there any other way to calculate hyper focal distance using mentioned camera and the lens?

You are correct in highlighting the fact that, because the distances can be so great, it is very difficult, if not impossible, to manually measure out the hyperfocal distance indicated on a distance calculator. This means that the use of hyperfocal focusing on such lenses is, in these cases, not recommended because it is not practical.

The alternative option and general 'rule-of-thumb' guide is to focus on something one-third (33%) of the way into the scene.

When taking a photo with its hyper focal distance should the focusing mode always manual?

When you are unable to manually measure hyperfocal distance and are using the 'rule-of-thumb' method, then if you are able to auto-focus on something one-third of the way into the scene, you can do so. Similarly, if you are using hyperfocal measurement, then so long as you are able to focus at the relevant distance and keep the focus at that point, then you can use auto-focus. The important point about this is that you know your camera well enough to be able to focus on a given point and then re-compose the picture whilst holding focus at that original place.

[arith]

Hyperfocal distance doesn't have to be exact does it? It not as if you are going to use a tape measure, I just pace it out one giant leap for me is about 1 metre.

If you set the focus on infinity, the hyperfocal distance is the nearest thing in focus with the dof button pressed. I read that somewhere but have never used it. Looking at a dof calculator might help since only a general idea is what is needed. I guess the hyperfocal distance of my 50mm on my APS-C or cropped sensor to be 15 metres @f8(it isn't but it's not going to make a lot of difference anyway).

So the hyperfocal distance @f8 of 25mm = 0.5 x 50mm is (0.5)^2 (half squared) times the hyperfocal distance of the 50mm or 15/4 metres about 4 metres. So now you can see a general rule and you could use a calculator on your mobile for instance or do what I do;

Calculate some of the hyperfocal distances and remember them, so you can do;
18mm=2 metres approx @f8
35mm= 8 metres
50mm= 16.5 metres actually @f8
and so on. But you might want to use f4 so just double the distances and f16 half the distances and everything else is somewhere in between.

eg for 18mm @f5.6 you know 18mm @f8 is 2 metres and f4 is 4 metres therefore I would guess it at around 3 metres or in any case somewhere in the interval (2,4). cheers I'm confused now

[sauron]

Thank you ..