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whaleshark

Member Since 27 May 2010
Offline Last Active May 03 2013 11:56 AM
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Posts I've Made

In Topic: Olympus Mirrorless vs RX100 Major benifits?

03 May 2013 - 11:49 AM

If you can find Jim Lyle here or on ScubaBoard, ask him about his Olympus OM-D EM-5 for underwater.

If you want more than 12 MP you need to consider the latest Olympus Pen, the E-PL5 or E-M5 (whatever they're called) or the more advanced OM-D EM-5. Look at the creative controls and manual exposure controls for all of these cameras. It should be easy to access aperture and shutter speeds for flash/distance exposure control. For Olympus micro 4/3 consider using the prime lenses, like the 60 mm macro lens or the 8 mm fish eye lens.. Any of the Panasonic lenses, like the 45 mm macro will fit it too. For more info about micro 4/3 lenses look here:

http://www.four-thir...g/en/index.html

The Olmypus housings look great but the port options are limited. See if they have options for installing other ports from 3rd party manufacturers. And consider the Nauticam housing for the OM-D EM-5. Here's a good description of the OM-D and the Nauticam housing:

http://reefphoto.com...roducts_id=5899

In Topic: Getting more than 1:1 macro from 1:1 lenses

03 May 2013 - 11:01 AM

I've found that a teleconverter does not add magnification but it increases the focal length and working distance. The mimimum image size is the same but you can achieve it from farther away. A 1.4 teleconverter reduces the light by one stop. A 2x reduces the light by two stops. Teleconverters generally don't work well on slow lenses but do work on f/2 and f/2.8 lenses. They reduce image quality, but not significantly on the faster lenses.

You have plenty of light with dual strobes so small apertures with a TC at macro distances are not a problem. No one wants to shoot macro wide open because of the negative affect on DOF. It just gets harder to autofocus when the minimum f-stop drops to around f/5.6 or f/8. Otherwise reducing the aperture is really not an issue for UW macro.
I'm shooting macro with the Olympus E-330 in an Ikelite housing and the 50 mm f/2 macro lens (100 mm equivalent). It provides 2:1 macro which is a 34 by 26 mm minimum image size. On Olympus 4/3 format, using the 35 mm f/3.5 macro lens allows 1:1, or an 18 mm by 13 mm subject size. That's a really small image size. For topside wildflowers and other macro I use the the E-5 with the 50 mm lens and a flash ring.

The 50 mm macro achieves 2:1 at a reasonable working distance, several inches away. The 35 mm macro lens achieves 1:1 at about 1" from the lens, or right at the lens port face. That's not useful underwater, but you can still focus the 35 mm macro at less than 1:1 magnification from farther away. The 50 mm is a better lens for UW macro on Olympus 4/3.
The 2:1 macro image size on 4/3 is essentially equal to what the full frame camera achieves at 1:1. The 4/3 sensor is only a little bit smaller than the APS-C sensor size. Apart from recent advances with newer APS models in high ISO and DR, the IQ and functionality is similar. For macro UW with strobes shooting at low ISO is typical so the differences are marginal.

An extension tube increases magnification without reducing the light. With the 50 mm f/2 macro and the EX-25, a 25 mm extension tube, it achieves 1:1 from a closer distance. In-focus range is limited to between 2" and 4" with the lens focused from minimum distance to infinity. I've used this combo a lot topside with a ring flash and the image quality is great. The subject size is as small as 18 mm by 13 mm with the Olympus 4/3 format.

For UW macro here are the downsides to using this 50 mm + EX-25 combo (and probably with any system): It's very hard to find subjects within the focus plane at that magnification. Everything is a blur until you bring the subject right into the focus distance. Autofocus is awful unless you're already close to correct focus. If you're too far away for the lens + EX it will never achieve focus. Shooting topside with the EX-25 I typically manual focus at anywhere from minimum to infinity and then move in until I achieve focus. It may be possible to arrange the Ikelite zoom ring to function as a focus ring even with the EX-25 in place. I put the zoom ring on the focus ring for both the 50 mm macro and the 8 mm fish eye lens since there is no zoom and it works well but you can not see the focus scale. For UW behind a flat port the 50 mm + EX may be far enough away At the available focus distances, but strobe lighting will be difficult.

I've found the Olympus 50 mm f/2 macro lens to be very capapble for UW macro. I haven't had any desire to increase focal length with the EC-14 because the 50 mm is far enough for most subjects. It's also challenging enough to aim and focus with just the lens so I'm not ready to make it more diffficult with a longer focal length.

As other people have said, I think achieving greater magnification than 1:1 underwater is probably better with a longer focal length. I may try this using an extension tube with the Sigma 105 mm or Sigma 150 mm f/2.8 macro lenses.

In Topic: packing and transporting my rig

03 May 2013 - 12:01 AM

 
There are lots of good ideas here. I learned a lot from reading all of them. I could not find the Samsonite F'Lite bag on their website. They have lots of other 30" rolling luggage hard cases that would work well. They're not cheap but lots of them are on sale for over 50% off.  http://shop.samsonite.com
 
I'm travelling to Little Cayman soon with a bunch of friends. We're flying on United to GC and Cayman Air to LC. The United baggage limits and fees are $25 for the first bag and $40 for the second bag. Two checked bags = $65. We get one carry-on bag and a personal bag, laptop bag or backpack. From Grand Cayman to Little Cayman the Cayman Air island hopper allows 55 pounds per person combined total in up to two bags and only one carry-on of 15 pound max. plus a personal bag. Anything over the weight limit is $0.55 per pound.
 
No one with dive gear and UW camera gear is going to meet the limits on the island hopper. On many of these small island hoppers they weigh you and your carry-on bags as well as your luggage. They have to know how much total weight they have on the plane.
 
The only reason I can meet these weight limits is because my wife doesn't take an UW camera.
Just your dive gear in a rolling dive bag weighs about 35 lbs. Add clothes, toiletries, a hat, a basic camera and a good book and it weighs 50#.

I will be carrying all of my cameras and lenses and small expensive accessories in my carry-on. I use a pelican 1510 rolling carry-on-sized bag because it's easy to pull through airports. I'll carry a medium sized daypack too. The housing, batteries and UW accessories go in the checked luggage. I've done this for many years on one and two leg trips and never had a problem.
 
I use a rolling Underwater Kinetics hard box. It weighs much less than a Pelican box and probably about the same as those Samsonite hard luggage bags (12 lbs and up). The Ikelite UW housing, dual Ikelite DS-125/160 strobes and spare batteries, arms, clamps, chargers, misc batteries, Fantasea focus light, flashlights
and accessories go inside the checked UK hard box. I wrap everything seperately in the lightest padding I can find - bubble wrap. Big rubber bands, rather than tape, wrap both ways to keep it rolled up and make it easy to reuse on the return trip. If you opened the box you'd see bunch of various sized packages in bubble wrap. The gear all fits in the box with some room to spare before I hit the 50# limit. I fill the rest of the case with more bubble wrap or open-cell foam. Open-cell foam does not expand in flight.
 
Leave the air vents open on your hard boxes when you fly. Otherwise they may pop open on ascent and if they vent slowly they can be crushed on descent. Same goes for toiletries and liquids in plastic bottles. Squeeze the excess air out before you pack them. 
 
My friends tell me to get TSA locks. I've never done this before but I will this time. I usually put black plastic wire ties through the lock holes. They can't be seen on a black bag or box and will stop anyone from opening it quickly. I've only had them cut once and nothing was missing.


In Topic: Removing scratches from a dome port

02 May 2013 - 09:57 PM

Thanks Udo,

 

I sent the port off to Ikelite. If I spent $30 or so for a polish kit and hours trying to do it right, I'd be better off letting Ikelite replace it for $150. The outside was pristine, with only minor marks. I would have considered the polish method if the damage were on the outside. The port will be near perfect inside and out now when it comes back.

 

I also had a bad dual sync chord that needed testing. Turns out it flooded and needs replacing. Ikelite gave me a better price for replacement so they're really standing behind their gear. I'll get the port and cord back before my trip. The shipping will be expensive for 2-day or next day air, but that's what happens when things break just before a dive trip.


In Topic: Removing scratches from a dome port

30 April 2013 - 09:01 PM

I did something really bad to my Ikelite 8” dome port this weekend. After not shooting UW for about a year I have been putting all the pieces together. We’re going to Little Cayman in a few weeks. I was testing the strobes and needed to put a lens on the camera. I had the super wide port body on the big dome but instead of mounting the shorter 8 mm f/3.5 fish eye lens I put on the larger 11-22 mm f/2.8-3.5 WA zoom lens. If you shoot with Olympus you know these lenses and how different they are in size. Both lenses are great underwater but they require different port bodies. I had my DIY neoprene port cover on and couldn’t see why the port body wasn’t engaging with the port locks. I kept rocking and rotating the dome trying to get it to seat.

 

To make a long violin solo short, I ground up the inside of the dome port on the knurled lens filter, making an ugly round mark. Ouch! I felt awful and awful dumb at the same time. Please don’t try to cheer me up by saying, “Duh, you should ‘a known better”, ‘cause that won’t make me feel any better. L LOL, I know I deserve it anyway. J

 

So Ikelite is being very helpful, as always. The acrylic dome can be replaced in my existing dome body and shade without having to buy the whole Dome Assembly new. It’ll cost me about $150 instead of $400. Gee, I feel a little better already.

 

I thought about this polishing method but it would be really hard for me to do this evenly on the inside of the dome. My hands are too big to fit inside and if I didn't polish the whole surface evenly the dome would have anomalies in the surface that would show up as distortion.