Help with shooting with Canon's 100mm Macro lens

[Mucksavage]

Hi All.

I'm not so much a beginner with UW photography but I am brand new diving with my Canon 100mm macro lens - 3 dives in all and it's been tough!

I am a Canon 40D user with Ikelite housing and strobes (DS160 and DS125). I have been shooting quite well for some months with a Sigma 17-70mm lens. I think I am OK lighting for macro and WA thanks to that lens' range. Now however I am mid trip and have got my 100m macro lens and port with me. I've struggled to get results. I know macro requires smaller apertures but even with half decent strobes I can't seem to get anything but a black shot on virtually anything lower then F8.

I've been very frustrated as I can't get a crisp shot on F5.6 (DOF is just too small) which seems to be all that exposes right. I'm keeping my ISO at 100 or 200. I just did a dive with a friend who shot with the Nikon 60mm and took everything on f22 with nice results. We shot the exact same stuff!

I thought it was maybe a lens fault but I'm sure it's the photographer.

Any tips or advice on how to maximise the 100mm?

Cheers

 

[SpiderSense]

how do you have your strobes pointed? sounds like you're not getting enough light. how are you shooting? manual? what is your shutter speed when you can't get the crisp shot?

disclaimer: next week will be the first time i shoot with my dSLR underwater, but since you're mid trip, i'll give you my thoughts. i'm assuming the techniques i use on land mostly apply underwater. and also hardly ever use my 100mm. having said that, this is how i would shoot macros with a Canon/Ikelite setup:

Camera set to Manual. set shutter speed to minimal to freeze motion. say 50 or faster. set aperture to control DOF.. say, f22. i generally keep my ISO at 800 if i'm looking for a brighter background. i don't mind the noise at 800 on the 40d at all. i'm never at 200 or below unless i want a black background.. focus set to ai servo with all points enabled (but use only middle point on your subject).

set strobes to be TTL and let them expose the subject. adjust compensation as needed.

when shooting, are your TTL strobes firing full power? if so, you might underexpose. re-aim the strobe and bump up the iso so your strobes don't max out.

i just did some tests with my 5d/ds125/ds125 last night in my house and i'm shocked how well Ikelite TTL exposes the subject. shocked! it almost didnt matter where i pointed the strobes. and nothing was overexposed. and with the 100mm at f22, DOF was huge and everything in field was in focus. super super sharp. i need to use the 100mm more often!

if you're getting blurry pictures, it could be motion blur = increase shutter. bump iso if needed.

if black or underexposed, then you're not getting enough light (for your settings). bump iso, check strobe, check strobe and exposure compensation setting, go wider aperture, go slower shutter.

 

[Mucksavage]

Hi there

Well I'll generally shoot on a shutter speed between 80 and 125. With the 100mm lens I'll start around f22 but will end up coming back to f8 or f.71. The strobes are tucked beside the lens more of less pointing forward. Any blur is DOF related I think.

Some time ago I posted a question here about matching an Ikelite DS125 and DS160 - I just revisited it and found an additional reply from Ikelite. Have a look and see what you think - it seems to suggest my combo wont work in TTL?? In fact the last reply doesn't quite seem to address the original question so more confused.

http://www.scubaboard.com/forums/ikelite/268012-pairing-ds-125-ds-160-a.html#post4159906




I'm sorry to have to recant my previous statement, but I've just stumbled across a more accurate answer.

You should be able to use your original (pre-2500) DS125 strobes in manual mode with the housing and a sync cord. Set the housing electronics to manual (which cancels the preflash) and choose a manual power setting on the Substrobe(s). I haven't tested this myself with an original DS125, but I believe it will work correctly.

Regards,
Jean / Ikelite
IKELITE Underwater Systems



I am reunited with my housing on Monday and will do immediate land tests like yourself.

 

[SpiderSense]

so what mode are you using?
Av, Tv, M ?

why are you going to f8? especially with a 1.6x crop factor on the 40d, you wont have enough DOF with a 100mm lens.

how does your technique work on land? try mine on land and see if it works.

the strobes are another part of the equation. are you shooting TTL? are your strobes/cables TTL capable? i doubt there is any problem mixing ds160 and ds125 substrobes, as long as both are TTL capable. the last post in that other thread refers to earlier generation substrobes that are not TTL capable (or even upgradeable). check your serial number.

practice on land!
don't be afraid to bump up the iso!
a noisy photo is better than a blurry one!

 

[Mucksavage]

I shoot manual and the only reason I'm at f8 is that I'm way under exposed otherwise and yes the DOF simply isn't enough at all.

I have switched to TTL of late but have taken most of my previous pics in manual, adjusting the strobes myself so my 'instinct' for TTL is a work in progress. In fact I am not completely confident in it. I've read so many posts about just how accurate it can be but I haven't found that just yet.

i have the dual synch cord from Ikelite and only started 2nd guessing the TTL compatability of the 2 strobes just now.

I do generally avoid bumping the ISO much beyond 300 but you have a point - noisy is better then nothing.

I have used this lens a lot on land but mainly for portraits and less for macro.

I'm going to get truly stuck into this next week, first land, then underwater and hopefully can crack it.

 

[sharkbaitDAN]

I use the 100mm lens for macro with my 350D/Rebel XT. I have thought that TTL consistently underexposes my shots, so I use the manual controls on the back of the Ikelite housing. I was just looking at the info for some of my macro shots and have good exposures at ISO 200 with 1/200 and f/13. I was using one DS-125. So I don't think the problem is necessarily your camera settings, though they could use fine tuning for other reasons.

One possibility is the strobes are preflashing when they are not supposed to. It will result in major underexposure, I have that problem with the inon Z-240s I use for work. the Z-240 has a push button that wants to be in preflash mode, but the dSLR doesn't use preflash. I realize now there might be a problem with the integration of Canon's TTL system and Ikelite's causing a preflash situation.

As to the second point:

I think Ikelite was saying if your serial number is lower than 2500, it will not work on TTL. There was a change in circuitry from the earliest DS strobe models, so that they only work on manual. I have this issue with a very early DS-50.

 

[Mucksavage]

Thanks again for all the responses.

Alex - do you use TTL and then bump up the power using the Ikelite switches on the housing? When I use manual I generally take a shot and then adjust on the actual strobes - full, half etc, and maybe fine tune with the housing buttons.

My DS125 is a latter day one so should have no TTL issues.

I will double check the pre flash but on my last dive I did fire the strobes to make sure they were working. Before I went blind they seemed to be fine - no preflash. Well lets just say there was one flash.

I had no problems with my Sigma 17 - 70 over the last few months, which is why my suspicions fell on the 100mm lens immediately - but perhaps its all strobe related alright.

 

[sharkbaitDAN]

I have the strobes set to TTL and use t.he controls on the back in manual mode to fine tune. Though the next time I take my own gear down, I will probably shoot in manual.

Just to clarify, you won't be able to see if the strobes are preflashing. It is a fraction of a second difference. They will go off, just a fraction of a second too early. At least this has been my experience with preflash strobes. They don't necessarily preflash like the internal flash will, they adjust their timing so that the flash goes off when it should as if there was a preflash.

Also to clarify, while inon's can be swithced between flash and preflash, the DS-125 cannot, at least to my knowledge. Whether it preflashes or not would be a function of the circuitry.

I agree that the fact things were working with the 17-70 and not the 100mm is odd. The only thing I can think of right now, is that you were using wide enough apertures/slow enough shutter speeds/high enough ISO to get decent exposures even without the strobes. Essentially working with natural light and not realizing it. I have this notion from experience, because I will start fooling around with my adjustments to lighten everything when I've really just messed up my strobe settings.

 

[Riger]

Hello all, interesting discussion..

I am considering taking my Canon 50D underwater (presently have a digital point and shoot underwater) and will be interested in seeing how this progresses. Mucksavage, if you have any high level advice for me before I commit funds, I'd appreciate that.

One question, is it fair to say that any testing done above the surface in a poorly lit room on subjects that are say within 2m of the camera, will be valid for underwater shooting at similar ranges?


Good luck and best Regards
Richard

 

[sharkbaitDAN]

Riger,

I would answer maybe, but probably not very useful. It may give you a general feel for the camera and lens, but the strobes are much more powerful in air than in water. You will get virtually no light penetration over 2m in water, but a strobe will have no problem lighting up a darkened room on land. This means a strobe at the same setting should correctly expose underwater but overexpose on land. The issues of backscatter and generally dealing with particulate matter is also moot on land. However, if you shoot natural light, learning low light shooting on land might speed your setup underwater.