Strobes & Full Frame Senors

I'm currently debating whether to house my D700.

Would a pair of DS160's provide enough power for a full frame sensor?

Comfortably.

Comfortably.

Cool - thanks!

I'm thinking about two different ways to go:

D700 + Ikelite Housing + Twin DS160's

... or ...

D200 + Sea & Sea DX200 Housing + Twin YS-110a's

There is no big need for particularly powerful strobes for FF cameras. I know some argue that you need more power to be able to use smaller apertures at FF and get the depth of field back. But many of the best underwater photos are taken very close to the subject where there is little need for lots of power.

Of course big strobes can always be turned down, but small strobes have the advantage of being more flexible with respect to where you can position them.

Alex

Full frame needs about a stop more light for equivalent DOF, but keep in mind that the D700 has a base ISO of 200. A D300 as a macro camera doesn't need a lot of light. Even though a D700 needs a stop more, maybe a stop and half, it isn't a great deal. I've mentioned it recently because people have been talking about strobes threatening small creatures. Some people also like to shoot macro subjects in continuous mode and the extra light may come into play there.

The biggest need for powerful strobes comes when shooting wide angle with sunballs and having to balance exposure at small apertures. Only the freaks who shoot super high magnifications need it for macro.

Thanks, guys!

Now I just have to choose between an older D200 and the newer D700. Tough call.

I'm now leaning D700 ... I think ideally I'd get the new S&S MDX and go optical, but that's a lot of $$$ for a housing that will get used one, two or three weeks a year.

That puts me in Ikelite-land (not a bad place) ... once there, I have to give the DS-160s a good look. I hate proprietary batteries, but a "free" TTL converter isn't something I can ignore.

I have a Canon 5D and when I use my 100mm + kenko 2x converter I need a lot of strobe light. Before I had 2 ikelite DS51 and I had to set my camera to iso 400 and f5.6-11 was the apertures I could use. I have a camera that could go to iso 50, but that will never happen with tiny/weak strobes. So it depends on what kind of lenses you will use in the future.

I have a Canon 5D and when I use my 100mm + kenko 2x converter I need a lot of strobe light.

Is this more to do with the 2x t/c than anything else though? My understanding is they 'soak up' a lot of light (for lack of better word - it's late and it's been a long day, brain's dead).

Ryan.

Is this more to do with the 2x t/c than anything else though? My understanding is they 'soak up' a lot of light (for lack of better word - it's late and it's been a long day, brain's dead).

 

Ryan.

Yes, thats right. converters "need" more light, but if you use the Canon 100mm at f22 1:1 it will need a lot of strobe light too. I have seen that weak strobes makes you set your camera so that the strobe light will be enough instead of changing the strobe power to the setting that you have chosen to your camera.

That´s why I use powerful strobes. They are a bit more bulky, but they give me the power that I want.

Yes, thats right. converters "need" more light, but if you use the Canon 100mm at f22 1:1 it will need a lot of strobe light too. I have seen that weak strobes makes you set your camera so that the strobe light will be enough instead of changing the strobe power to the setting that you have chosen to your camera.

That´s why I use powerful strobes. They are a bit more bulky, but they give me the power that I want.

I would think a 2x converter would steal two full stops.

My 1.7x eats a stop and a half - i.e. my 70-200/2.8 becomes a 119-340/4.0.

On my 70-200, I find the 1.7x really impacts sharpness quite a bit ... are TC's less "damaging" to IQ when used with prime macros versus telephoto zooms?

I would think a 2x converter would steal two full stops.

 

My 1.7x eats a stop and a half - i.e. my 70-200/2.8 becomes a 119-340/4.0.

 

On my 70-200, I find the 1.7x really impacts sharpness quite a bit ... are TC's less "damaging" to IQ when used with prime macros versus telephoto zooms?

I´m not sure about that, I have only used my TC with my canon 100mm and the IQ have been excellent. I use it in manual mode only so it can be tricky to get the right focus.

A 1.4x takes one stop of light and a 2x is 2 stops of light. Each effectively increases the aperture by one and two stops respectively. Because of that, shooting a 100mm + 2x at f/22 is equivalent to f/44. That's why it takes so much light. Doing so also results in soft images. If you shoot your 100mm at f/11 with the converter then your diffraction will be equivalent to f/22 and the light required will be the same. Teleconverters soak up light needed for focusing but they do not need extra light as long as you are adjusting aperture to comparable sharpness.

In other words, imagine have a 100mm + 2x converter and a straight 200mm macro lens. The 100mm combo will likely have a wide open aperture of f/5.6 which is dark but adequate for AF. The 200mm will likely be f/4 or a full stop brighter. The 100mm combo will get to 2:1 without diopters whereas the 200mm will only do 1:1. With a wet diopter, both will give a lot of power. If you shoot the 100mm at f/11 and the 200mm at f/22, you will get comparable DOF but the 200mm will give a sharper image overall. They will require the same strobe power. You would never shoot the 200 at f/44, even it it were an option, so why would you shoot the 100mm combo at f/22?

A 1.4x takes one stop of light and a 2x is 2 stops of light. Each effectively increases the aperture by one and two stops respectively. Because of that, shooting a 100mm + 2x at f/22 is equivalent to f/44. That's why it takes so much light. Doing so also results in soft images. If you shoot your 100mm at f/11 with the converter then your diffraction will be equivalent to f/22 and the light required will be the same. Teleconverters soak up light needed for focusing but they do not need extra light as long as you are adjusting aperture to comparable sharpness.

 

In other words, imagine have a 100mm + 2x converter and a straight 200mm macro lens. The 100mm combo will likely have a wide open aperture of f/5.6 which is dark but adequate for AF. The 200mm will likely be f/4 or a full stop brighter. The 100mm combo will get to 2:1 without diopters whereas the 200mm will only do 1:1. With a wet diopter, both will give a lot of power. If you shoot the 100mm at f/11 and the 200mm at f/22, you will get comparable DOF but the 200mm will give a sharper image overall. They will require the same strobe power. You would never shoot the 200 at f/44, even it it were an option, so why would you shoot the 100mm combo at f/22?

I never use f22 when I shoot with the 100mm + 2x TC, it´s just when I shoot with the 100mm without TC and I want that extra DOF. What I mean is that I would like to use iso 50 or 100 and that´s not possible with weaker strobes, but that´s not a problem anymore when I use my subtronics.

On my 70-200, I find the 1.7x really impacts sharpness quite a bit ... are TC's less "damaging" to IQ when used with prime macros versus telephoto zooms?

The short answer is no, IQ is damaged by TC's regardless.

If a TC were optically perfect it would deliver its intended magnification without any degradation of its own. That means all the flaws and diffraction of the main lens are magnified. Degradation is inescapable.

That doesn't mean you shouldn't use TC's. My experience is that 1.4x is OK and 2x somewhat less so, but given the choice I'd rather choose a macro lens with the focal length I need than to add a TC to one I've already got. Of course, this issue has nothing to do with how much light is needed for full frame. Adding a diopter to a lens of the right focal length should be kinder to IQ than a TC but you should always test.

Of course, this issue has nothing to do with how much light is needed for full frame.

On that ... let me paraphrase and please tell me if I have it right.

For Macro:

To get the same DOF with the same FOV, you need about 1 more full stop of light on a full-frame camera as you would on cropped. Since the "right" amount of light (for cropped) for can be delivered without maxing out a strobe like a DS-160, there is enough "headroom" to light the same shot for a full-frame camera with such strobes.

For Wide Angle:

DOF is not the issue, balancing the foreground subject with the ambient light is ... and the same challenges are faced by both FF and cropped cameras ... there are just times when it is almost impossible to have "enough" light to illuminate the foreground subject against a really bright sun. Here's power is key regardless of sensor size.

Yes, provided the cropped and full frame cameras have the same ISO rating. A D300 will require 2 stops less than a 5D2, one for sensor size and one for the difference in base ISO. I think you'll find most strobes are still adequate though it becomes closer.

For very small subjects, bellows factor effects full frame more so the one stop difference becomes a little greater. Not a big deal but I'm being thorough.