Question about macro lens - 50mm vs 100mm

[montychandler]

I have a question about the use of a 50mm macro lens versus 100mm. I shoot with a Canon 20D, Ikelite Housing, dual DS125 strobes @ 1/8th, flat port for the 50mm. While I generally love the result I get with the 50mm and its versatility there are many times when I'm shooting a small subject that I only get a part of the subject in focus. Of course this is generally when I am getting in really close.. My question is - if I were using a 100mm getting greater magnification at an increased distance, would this acheve the closeness and magnification while at the same time obtaining proper focus of the entire subject?

I'm thinking this is true, but before I go buy a 100mm lens I want to be sure that this will be the result - no better folks to ask than other people who understand the challenges of taking photos below the surface.

I've attached an example of what I am experiencing. Thanks, Monty

 

[ABQdiver]

Your aperture is at F/2.8 for that shot. You might change your DOF (depth of field) by making the aperture smaller, that will help get more of the subject (and background if you want) in focus. Try using F/8 or so, it will make a difference. The EXIF info also says you're using the auto exposure mode. Try changing to aperture priority or manual. Its' quite amazing what kind of changes you can get with just changing the aperture.

This is a pretty good article that says it better, (with less typing on my part)

 

[alcina]

With a dslr lens use your aperture range - I shoot at f22 a lot of times. You aren't limited to f8 which will still be very shallow on the macro lenses.

If you are shooting dslr especially you really need to switch to manual mode. Aperture and shutter priority also have their places, but manual is the way to go dive in and dive out.

 

[montychandler]

Thanks guys for the feedback. I do appreciate it. The ongoing education continues. Alcina - My wife and I read with great interest your cozumel trip report. We dive Cozumel quite often and had never considered the shore diving (really thought it was more snorkel oriented) but after reading your thoughts, we're going to give it a go..

TA,

 

[Diver Dennis]

Hi Monty. I use the 100mm and shoot between f/8 and f/14. Here are a few here that are almost all shot with the 100mm and a Rebel XT. It is kind of a long thread but there are photos throughout. One good thing to remember is that the 100mm has a shallower depth of field than a 60mm or 50mm but you don't have to get as close to the subject.

http://www.scubaboard.com/showthread.php?t=147109

 

[montychandler]

Thanks Dennis. I enjoyed the browse - some very nice captures throughout the thread. I'm going to bring some models down to the camera store I should just about OWN by now, and play with a 100mm they are bringing in for me.. I'm going to try the switch to Aperture mode on my 20D and see how things compare between the 50mm and the 100mm. I can't go to full manual cause I'm an old guy and use reading glasses. There no way I can be changing the settings on my camera while I'm doing everything else I'm doing underwater getting the shots I want.

There's a bit of urgency in getting this sorted out and then comfortable with the change as we're heading off to St. Vincent in October. Normally I don't have an issue getting close to my subjects and just hovering there while they pose properly , but I hear St.Vincent can be a little more silty and therefore the 100mm may be a better option, especially since there will be more divers in the water than I usually dive with and they'll all have cameras. We'll see.

Thanks again,

 

[alcina]

If the water is dirtier, I prefer the 60mm macro (or 50mm). The farther away you are from the same subject the more water and particles you have to deal with so the 100mm may be tougher.

I don't think the 100 and 50 have different DOFs...DOF is a function of your aperture and distance - think what happens when you zoom in with a compact. There are some seriously intense discussions about this on the web, but I wouldn't worry about it too much. Just remember you can use different apertures to obtain the look you want.

The 60/50 is harder to light when you are in close, but I like it as it's a bit wider for those "other" non- macro shots. And closer is better underwater. But as with everything, there are trade-offs. I have the 100mm macro, too, and it's a great lens. I think they are both definitely worth having and using.

I didn't manage to get a shore dive in this last time, but defnitely will in January when we are there. I believe it has changed quite dramatically since we were there in 04 but change isn't always a bad thing...