Focus Question Pic Attached

[danny wdr]

What should I do to get the barb wire and the sunset in focus:mad2:

[Frog]

I doubt that you can when you are that close to the wire and its in focus then the background is going to be out of focus.
You could try a smaller aperture...f/22, f32, whatever your lens allows.
Or, another thought is use a more powerful lens so you can be farther away from the wire.
No idea what might do it....400 or above I'm sure.

[danny wdr]

thanks frog, I will give it a go with the 500mm

[Medley]

Actually, you want a LESS powerful lens.... ie wide angle.

The hyperfocal distance of a lens is the shortest distance that gives the greatest depth of field. In other words, it's the shortest distance where everything behind the subject is in focus. (You'd need an infinite 'far' focal distance to have the sunset in focus)

The metadata lists your lens as "105mm". With a 105mm lens at f22, the hyperfocal distance is 80.3 feet. Assuming that you were focused on an object 80.3 feet away, the depth of field (in-focus area) would be between 40.15 feet and infinity. So you could have the fence about 40 feet away, but your focus would still have to be at 80.3 feet.

The hyperfocal distance of the 500mm, at f22 is 1814 feet. At that distance, the depth of field would be between 907 feet and infinity. NOT the optimal solution.......

Assuming that the 105mm lens is the 18-105mm kit lens, try it on the 18mm end. If I'm right, the hyperfocal distance of the 18mm end at f22 is 2.41 feet, and the depth of field would be between 1.2 feet (about 14.5 inches) and infinity.

The only thing I'm not sure on is if you can do the computations that way on a zoom lens, or if the hyperfocal distance is the equivalent of the largest end of the zoom (in this case, the 105 mm end). Still, it would only take one or two test shots to figure it out.

- Joe U.

[Medley]

Oh, and for reference, I'm using the online depth of field calculator at this site to do the computations:

http://www.dofmaster.com/dofjs.html

I'm sure that someone here provided me with this link, and if I could remember who, I'd gladly give them proper credit...........:blush2:

- Joe U.

[OldClicker]

Actually, you want a LESS powerful lens.... ie wide angle.

The hyperfocal distance of a lens is the shortest distance that gives the greatest depth of field. In other words, it's the shortest distance where everything behind the subject is in focus. (You'd need an infinite 'far' focal distance to have the sunset in focus)

The metadata lists your lens as "105mm". With a 105mm lens at f22, the hyperfocal distance is 80.3 feet. Assuming that you were focused on an object 80.3 feet away, the depth of field (in-focus area) would be between 40.15 feet and infinity. So you could have the fence about 40 feet away, but your focus would still have to be at 80.3 feet.

The hyperfocal distance of the 500mm, at f22 is 1814 feet. At that distance, the depth of field would be between 907 feet and infinity. NOT the optimal solution.......

Assuming that the 105mm lens is the 18-105mm kit lens, try it on the 18mm end. If I'm right, the hyperfocal distance of the 18mm end at f22 is 2.41 feet, and the depth of field would be between 1.2 feet (about 14.5 inches) and infinity.

The only thing I'm not sure on is if you can do the computations that way on a zoom lens, or if the hyperfocal distance is the equivalent of the largest end of the zoom (in this case, the 105 mm end). Still, it would only take one or two test shots to figure it out.

- Joe U.

To get the same image (field of view), focal length is cancelled by distance, isn't it? With the wide angle, he will either have to move closer (which defeats the point of the wide angle) or crop the shot to get the same image. With a longer lens, he would have to back up; again defeating the purpose.

If the smaller aperture doesn't do it, you would need to go to a multiple exposure and blend (or change focal length or distance and crop).

TF

[Medley]

Indeed, he may have to crop either way. And multiple exposure is always an option (though you would have some cloning to do to get the OOF barbed wire out of the way).

But the question was how he got both in focus. I simply assumed he would know that you could do that with two exposures (it DOES kind of stand to reason...) and was asking for a single-shot solution.

- Joe U.

[Frog]

I was thinking that if he used a longer lens that he could be further away and still have the composition of the close up wire and then also have more dof.
I'm not good with the numbers thing so it will be interesting to see results.

[danny wdr]

Thanks everyone, as soon as I get a decent sunset I'll be back to the fence lol.

[Greg McCary]

Photoshop it. But I doubt you will get both in focus out of camera. If you did photoshop it I don't think it would look right.

[Skyman]

Photoshop it!

I remember watching a tutorial about dof in photoshop where they had a series of photos with a shallow dof but they wanted a shot with greater dof so they took several shots, shifting the focus point throughout so that every element of the photo was sharp in one of the photos. Photoshop then did some auto layer, selectively mask and sharpen, so the end result looked like it was taken with an aperture of 300 or something. I guess this is the DOF equivalent to HDR and probably comes in very handy for macro work!

[Medley]

Photoshop it!
I guess this is the DOF equivalent to HDR and probably comes in very handy for macro work!

There's a plug-in for Photoshop called Helicon Focus that does this as well.

- Joe U

[danny wdr]

all I can say is photoshop, which I dont have

[Skyman]

depends how "real" you want to make it. there are plenty of programs that will let you layer a photo these days. You could even take a photo of the sunset and a photo of the wire and layer them. If you want to do it in camera then really small aperture and playing with focal lengths until you get the depth of field you need is the only way. You might find that focusing somewhere between you two subjects works best. The other option is to play with hyperfocal settings.