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Glasseye Snapper

Member Since 11 Oct 2005
Offline Last Active Feb 26 2015 05:58 PM
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Posts I've Made

In Topic: Panasonic LX-100 Nauticam housing

04 February 2015 - 05:56 PM

I'm a bit confused by the table as well especially looking at the LX-7, which has at least 20% more focal length than the LX100. I suspect 32mm is doable since the Subsee+10 is giving about 4.5cm. So may be the CMC-1 is closer to +15, which is stronger than the SMC.

 

For diopters what matters is the optical focal length, not the 35mm equivalent value. With the LX100 having a larger sensor perhaps it has a longer optical focal length than the LX-7, which would make the diopter work more effectively. I am more puzzled by the fact that they increase magnification while at the same time increasing working distance. It is hard to imagine how that would work for a diopter, or any other type of solution that I know of.

 

Bart


In Topic: Olympus 60mm macro focus distance display.

28 January 2015 - 05:55 PM

At 1:1, closest focus is 7.5 inch but that is measured from the sensor. Subject distance in front of the lens will be about half of that. A bit less again due to the port. This parameter is not intrinsically dependent on sensor size and a 60mm APS-C lens, or a full frame lens if one existed, will have equivalent subject clearance. The reason that a full frame camera appears to lead to more working distance is that people use longer focal lenses to get the same field of view and, for instance, a 100mm macro lens will have greater working distance.

 

Bart


In Topic: New Olympus WA lenses

14 January 2015 - 06:33 PM

Hi Oskar,

 

Is it the anticipated higher optical quality or the extra light you are most interested in. From recent discussions on shooting wide angle lenses behind a dome I got that you need to stop down to get sharp corners. In that case the only benefit from extra light is during focusing, which may not be that much of a deal.

 

Bart


In Topic: Olympus 60mm macro focus distance display.

18 December 2014 - 05:25 PM

Hi Bill,

 

I used exiftool to extract the information (free download) for my EM-5. I posted info on how well the distance allowed you to calculate the actual size of subjects in your image. You can find the post here http://wetpixel.com/...showtopic=52938

 

Bart


In Topic: Triplefins X 2

16 December 2014 - 05:05 PM

Thanks for the update. E. tutuilae is in my books but I would never have guessed it. The description states that is the most widely distributed and most common species of the genus and that its coloration is variable. The one thing Reef Fishes of the East Indies is less good in than the Reef Fish ID books is hightlighting exactly what aspects of the appearance are visually distinguishing marks. Fin ray counts may be of interest to their scientific audience but for us visual ID cues are critical.

 

By the way, the image for the male shows it with a bright red cheek, chest and leading part of the central dorsal fin. The description never mentions it so I expect it may be a mating or territorial coloration. It is supposed to also occur in the Red Sea so I can keep a look out for it on my next trip in May.

 

Bart