Best way to achieve tack sharp focus?

I have been shooting landscapes for years. I can not stand when my photos are not tack sharp. I have spent a lot of time in trial and error learning the best techniques on land to get this sharpness. I am new to underwater photography and am starting from scratch. Thus far, it has been very frustrating for me. I have gotten many "good" photos, but they are all soft to me. Nothing close to the sharpness I see from many of the people on here. I know experience will be key, just as it was on landscapes. However, while shooting landscapes is something I can do every day, going diving is not something I have the opportunity to do daily so learning takes far longer.

I shoot with a canon 5d ii, 15mm fisheye as well as a 100mm for macro. I have dual ds160s and an aquatica housing. For ports, I use the 9.25 megadome for fisheye and the manual focus glass port for macro. There are two things I can think of to get better focus but I wanted to get some advice.

1st: a focus light. When I use auto focus, my camera takes forever to focus (one of the major failures of the 5dii in my opinion, horrible autofocus speed) I think a focus light would help big time. I also find that even when the autofocus locks, it is incorrect. Hopefully a focus light could fix both.

2cnd: for wide angle, I shoot mostly turtles and seals. I was thinking, if I were to set an aperture of about f11 and a distance of 3ft on the 15mm, that should give a good bit of wiggle room in depth of field. Does anybody do this? Dive with a preset focus? Seems like it would solve my problems of the lag time of autofocus.

Thanks in advance for the help.

Jim

Hi Jim.

I have a similar setup but in Nikon Dx format with dual Ikelites161's with Aquatica housing.

From my experience I would have to agree for your macro shooting a good focusing light is essential. I use the Itorch Video pro 6 with its 2400lumens and multi level output. Its great for macro still and video.

Regarding wide angle I can only comment on my Tokina 10-17mm FE on my Nikon D7000 behind a 8 inch dome. But my autofucas is very fast and spot on. But I also use single point focus as I found that its the fastest and most accurate AF in my setup. Using continous AF or multi point made the AF search and accuracy was way off most times especially when you needed it with fast action and close range shots. The tokina on AF and single point hasnt let me down much to date.

Hope this helps.

Regards Mark

Use the fastest shutter speed within your shooting parameters!

Enough DOF needed do use the right diaphragm setting. A hyper focal solution you are thinking off will not work. The image that the camera focuses on is a virtual image at a distance of about 1,5 x the diameter of the dome.

Thank you everybody. Mark, unfortunately, I am using single point auto focus and it is still intolerably slow. I have missed so many shots waiting for autofocus. I just ordered a sola800. I wanted the red light option as well. Hopefully this helps! Thanks again everybody.

Try locking focus on your fin. If you want to focus at 3 ft actual distance you must focus at the virtual image equivalent distance which is substantially less.

Something to make sure of for macro at least is that your lenses are actually focusing where you think they are. In my hands at least the 5dII is quite fast to focus but you will need a good focus light. Check your autofocus on land (Fusion works well and there are tons of home made solutions as well) and make sure it focuses where you want. Then also remember that most water is not anywhere as clear as most air (except maybe in some parts of LA) so what you find acceptable in a landscape will not be achievable under water, although Hawaii has great water. For wide angle remember the virtual image and focus on your hand (or fin) and go from there.

Bill

Thank you everybody. Mark, unfortunately, I am using single point auto focus and it is still intolerably slow. I have missed so many shots waiting for autofocus. I just ordered a sola800. I wanted the red light option as well. Hopefully this helps! Thanks again everybody.

Which 15mm FE are you using and how does it go when using in single point AF outside the housing?

Regards Mark

Thanks again everybody. I am confused about the virtual image part though. Why would focusing on my hand or fin be helpful? Mark, I use the 15mm sigma and it focuses very sharp on land. It is just very slow in the water. I was trying to shoot some waves the other day and ended up using manual focus because i kept missing the shot with autofocus. I bought a sola 800 so hopefully that will help. Thanks again everybody, I hate feeling like such a newbie after so many years of shooting but shooting underwater is a whole new ballgame!

Jim

Hi.

Macro:

A Focus light will probably help. With the Focuslight you might scare some creatures. Be careful using it!

You can prefocus pn a spot where the object Returns to. You can prelock the Focus and move back and forth until it is in Focus.

Wideangle:

The particles in the water softens up everything, unless it is gin clear. To avoid this. It is just to reduce the amaount of water.

Focus:

Sometimes it can be low contrast while UW. Try finding something with a bit more contras to focus on.

Very good advice. I guess I just need to spend more time in the water until I can get it all down

True! We all need more time in the water ...

some very interesting information here, thanks guys. Just waiting for my uw kit to arrive, so reading up on everyones thoughts!

I shot the 5D MkII for several years, and liked it. The Mk III was a vast improvement on focusing in low light. But I want to offer some specific pointers.

First, set your autofocus to single focus, without tracking.

Next, separate your focus OFF of your shutter, onto the back of the camera. This means you will use the back-focus button to achieve focus. Then, you can gently move the camera back-and-forth to get the image tack sharp in your viewfinder (I use a 45 degree one on the Aquatica housing).

But a major thing to check on your camera: The little diopter adjustment wheel on the right side of your eyepiece viewfinder could be off. What I mean by this, is if you set up some test shots (keep notes of what is and is not in focus), then compare to the actual downloaded images. The camera sensor does not necessarily match what you see in your viewfinder. This is especially critical in macro, with shallow depth-of-field. So it is very important to make sure that your viewfinder adjustment is actually giving you the image you think you're getting. Another "work around" on this is to "focus bracket". This means you focus on the point you want, then take a series of shots at that point, then slowly move the camera away from that point (while shooting frames), then move it beyond that point (while shooting frames).

Don't get frustrated with macro. It's a lot of fun, but requires a lot of patience. The focus light will help, but is not a cure-all. You can also try using the focus lights on your strobes to help, too.

Definately the Back button focus is the best single thing you can do for Wide Angle especially. Trying to lock the focus and re compose while underwater is awkward and not the best way. Separate the two functions and you will have a lot better results.

Pre focusing is not the answer.

There is some great advise here guys. I am just wondering about whether using the live view mode instead of the view finder effects what appears to be in focus?

Thank you

The live view can work, but you then have to "enlarge" the screen. I have seen people use accessory monitors, that have a very high pixel count, to help with this. Also, you need to find the "sweet spot" on your lens. If you stop down too much, you lose a lot of sharpness on your image. I have found for macro, around f/11 works well with my Canon 100mm L series. Alex Mustard has many good posts that show different sharpness levels, based on different apertures.