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rtrski

Member Since 13 Jul 2007
Offline Last Active Today, 06:44 PM
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#345804 Physically small intervalometer

Posted by rtrski on 07 April 2014 - 05:25 PM

Here's another small DIY unit (perhaps not as small as the one Bill linked), especially out of the case. I was lazy and emailed the designer for a prebuilt; he does have those periodically. And for out of the water these do a lot more than just intervals.  http://doc-diy.net/photo/smatrig21




#342293 Why are there so few housing / strobe combo with hotshoe connection?

Posted by rtrski on 23 January 2014 - 07:49 AM

You've got it right - that is a trade-off.  You're still going to be limited by the external strobe unit recycle time if not using onboard flash, although admittedly those have much bigger caps and batteries and can fire off pretty darn fast when not doing full dumps.

 

To me the 'ideal' approach would be a mini, TTL-capable, hotshoe-connected unit internal to the housing that just flashes an LED in fast enough sequence to provide preflash, flash, and quench information optically to an external strobe, which provides optical mimicry of that sequence/duration.  Since that unit would only be firing off very small LEDs with enough light to illuminate a well positioned fiberoptic sensor, it shouldn't have a slow recycle at all and prevent firing off the camera as fast as your main strobe recycle allows, at least.  But no one has marketed something like that yet.  (A few of us have built very simple little LED-strobes that just use the 'sync' signal to trigger, but that means no TTL or preflash, just manual triggering.)  Wouldn't even have to mount "on" the hotshoe - Ikelite's TTL electronics baseplate probably has room for a couple coin batteries, a few more caps and a FET to fire off a couple small LEDs, and their clear housing would let you mount an external fiberoptic fitting almost anywhere without a penetration.

 

But right now there seems to be a few TTL circuit options (Ikelite housings cabled to their own strobes, TTL adaptors by 3rd parties), a few optical-TTL options (Inon and others mimicking onboard flash),  and a lot of manual options (both electronically and optically triggered).  It may not seem like many choices, but we're a pretty small market overall...




#342201 Why are there so few housing / strobe combo with hotshoe connection?

Posted by rtrski on 21 January 2014 - 11:27 AM

It's not necessarily that it's expensive - as someone else already posted, Ikelite provides it as a rule on all DSLR housings, providing conversion circuitry to interpret / provide communication from the camera for TTL out to their strobes.  The question is one of getting the same TTL functionality without the hotshoe connection.

 

Inon strobes provide optically-slaved TTL mimickry - they'll perfectly match a camera's onboard lamp in terms of preflash, mainflash, and quench.  So...why have the electronic cabled connection (which must penetrate the housing, thus provides an extra potential leak path) to the flash?  If the camera "thinks" the lighting is being provided by its own onboard flash and is still able to 'control' the external unit by saying "got enough light- quench now!" the user hasn't lost anything aside from perhaps some battery life in the camera since you are firing the onboard flash (and the need to provide good internal light protection in the housing so the onboard light doesn't illuminate the interior of the port, etc.)

 

Factor in whether or not TTL really "helps" in many cases and manual can be quite good enough, and you have your answer.  Different vendors have picked different paths to the end requirement - adequate control of external lighting - and only a few have decided to pursue a wired TTL route.




#341977 UW photo gear in carry on - any no-no?

Posted by rtrski on 16 January 2014 - 01:01 PM

Expect a hand-check of a carried-on photo bag, whether its underwater or just a full photo gearbag in general.  Never had an issue with strobe arms specifically, myself, and mine are the bulky 'floatation' type.  They're pretty clearly hollow by weight and sound when handled, which helps.

 

I've even had a couple small hand-built circuits (LED trigger for hotshoe mount) that were fine as long as I could short across them and flash the LEDs with a coin to show what they did.

 

The one caution I have regards tools - they can get kind of snippety about screwdrivers and even tiny allen wrenches, so might want to move those to your dive bag.  A typical rubber-strap-wrench (for dome to port extension threads) typically goes uncommented though.




#331586 Spare Body or not

Posted by rtrski on 19 May 2013 - 07:37 AM

Spare body makes sense if you don't have electronics in the housing to also fry, which generally means fiberoptic triggering...but you might lose a lens along with the body, so where does it end?  Spare body is also nice if doing a combination dive/topside trip of some sort,  even if you're not hiking/touring around, since you can have the spare with a different lens available without having to break everything down. When someone yells "dolphins at the bow!" and your camera is in a housing with arms and strobes that's some 25lbs out of the water, boy do you want that spare to have been available.




#326002 3D Printed and Fiberoptic Ring Flash

Posted by rtrski on 10 February 2013 - 07:36 PM

Well, first draft is finally finished.

Dropped down from the 10.5mm lightpipes (the focus lamp pipe) to 5.6mm for the strobe light carriers...8 or 9 10.5mm pipes were too stiff. 8 pipes each lamp off the z240 for 16 total. 3D printed the 'cuff' for the port end and the strobe face cover and pipe mount. The strobe face cover attaches to the z240 with stainless hardware using the same threaded holes as the diffuser that comes with the strobe.

This might almost be too much light. Shots at 1/160th, F10-12, ISO400, and the strobe set at minimum manual setting (EV -6.0, 1/64th of full dump) are about as brightly lit as I think I'd want in a dark room. I actually have to use the focus lamp in that condition*. That leaves plenty of headroom for even narrower apertures and/or lower ISOs.

Sending one off to a beta tester in the next couple of weeks, hopefully can get some feedback of things that need changing before my own first dives with it (trip in late April planned).

Pics up at Flickr: http://www.flickr.com/photos/rtrski/sets/72157632741617450/

...using the Ikelite 5505.58 for a Sigma 105mm macro and an Inon Z240 Type IV.

The Saga ring flash (certainly much better built, with more but much smaller fibers - no idea of relative light transmission) runs something like 800 euro I think. This one, if I chose to sell it, would come in at significantly less than half that, if there was any interest. Will await my beta tester's comments and my own experiences in April before I consider it for real....but feel free to PM me if you just must. Posted Image

[* My camera is the Sony SLT-a55, which was from their first generation SLT's with the electronic viewfinder (EVF). These cameras have a 'helpful' feature that takes into account the exposure settings and darkens or brightens the view in the viewfinder accordingly, kind of a pre-shot preview or 'what you see is what you get'. UNFORTUNATELY the camera doesn't know when you have a manually attached strobe (no TTL communication)...so manual settings like the above result in a black viewfinder, although the camera has plenty of light to autofocus etc. The SLT generations that followed have a menu setting to turn off this 'help' in the EVF so it always shows a reasonably ambient picture (I don't think they cared/thought about underwater phtogs but studio photogs sure complained that the first generation didn't work with remotely triggered strobes), but mine alas does not, hence I get to use the focus light under circumstances like this. I may have to adjust a subsequent build of this part to have fewer pipes and provide a little less flash (and just don't get to dial the strobe down as much).]


#321783 Print-it-yourself zoom gear (Oly m.zuiko 12-50mm lens)

Posted by rtrski on 01 December 2012 - 06:50 AM

10.5mm lightpipes aren't very flexible, but they don't have to be. I think the minimum bend radius is about 70-80mm. I happen to have a local company that distributes all sorts of fiberoptic lighting supplies I was able to check it out at, but I'm sure they're just ordering direct from someone else anyway:

http://www.wiedamark...resideglow.aspx
(Don't let the fact that I linked to the 'side glow' fool you. The only difference between endglow and sideglow in solid core fiber like this is whether they add another black jacket atop it. I can add shrink tubing where I want/need it)

I was planning a hexagonal arrangement: 3 pipes each side of the lens, plus maybe routing the focus lamp light to a seventh. Plus if I get creative with my collar and the lightpipe clamps, I could group them together behind diffusers (you can print transparent ABS now too) or allow the user to move them wherever they wanted. Current CAD model (the black central part is the solid of the Ikelite port outline, only one diffuser currently shown at right) is attached. One of the things I'm a bit uncertain of is if I want to risk having the diffusers stand a little 'above' the port tip. Too far forward and they'll light up the port face itself and reduce contrast. Too far back and you get port outline shadows again. The Sage fiberoptic assembly just ends in the individual fibers well in front of the port face, but provides some adjustment. Not sure I want to go to all the trouble of having thumbscrews etc. to allow that.


Not sure I was trying to make money when I bought the printer, but it would be nice to sell just enough parts to pay back the initial investment itself (mine's a Solidoodle, considerably less starting cost than the Up!), and maybe free up money by printing a few parts like this that I can spend on other things like lenses instead. Posted Image

Sorry if this seems like a thread hijacking - just excited to talk to someone else doing 3d printing for u/w use. I see some of Reef Photo's parts (Reefnet brand) are 3D printed. Much as I like and respect them as a seller, and have bought from them (strobes etc), I can't see them continuing to sell things like strobe face snoot adaptors for $140 when they're clearly 3D printed parts.

Attached Images

  • Ringflash_collar_and_fittings_in_work.JPG



#321290 Water dispersant on acrylic

Posted by rtrski on 23 November 2012 - 06:02 PM

Please do not press the shutter button while licking your dome. That is NOT a pleasant picture. (Look honey, it's the frobulous pink sea cucumber octofish, it just swam right up onto my dome! Those little buds are all its tiny little feet....)


#321289 Compass mount for Ike Housing Handle/tray

Posted by rtrski on 23 November 2012 - 05:46 PM

Bought a compass some time ago on a retractor, when the wife and I gave up our console computers for wrist mount, and switched to just small SPG's on the braided HP hoses. (Yes, I know about the recall - they're swapped already). Compass on retractor was kind of bulky and frankly I never really liked it, it was obviously the same unit they also just put bungies on for wearing on a wrist, but I didn't want to do that either since I also wear a dive watch as a backup time/depth unit. Rarely do we get out of sight of the boat, even on trips to the Flower Gardens where navigation is 120% the responsibility of the 'buddy team', but I still didn't want to not carry one.

So, this was the obvious first easy project for the new 3D printer. Aside from all the endless projects just making it functional in the first place...:grump:

Posted Image
compmnt_assmbled_use2 by rtrski, on Flickr

More pics with descriptions of the design approach are in a small set at Flickr:
http://www.flickr.com/photos/rtrski/sets/72157632085470014/

Might also work on a 'clip' to wrap around the SPG boot to mount one on the back for the wife, although the SPG isn't on a swivel at the end of the hose, so that might not be the best treatment of it.....

p.s. WHOA!!! The new Forum software auto-plays Flickr set links as a slideshow??? Too cool, and a bit showoffy. Sorry, just meant to provide a link for the curious, not force-feed you all. :/


#316877 Considering new Nikon D7000 - would appreciate comments/alternatives

Posted by rtrski on 21 September 2012 - 08:17 AM

For one, Auto focusing with the Live View on is, to be polite, mmm... lame at best, (Most DSLR cameras use a different AF method than compact camera do) and manual focusing with a LCD is not the easiest IMO, also holding a substantially bigger and heavier camera and housing at arm length with somewhat slow shutter speed is asking for blurry shots, but on a more personal level, I feel that looking through a real optical viewfinder make me concentrate more on the composition, what you see is the definitive image, no surrounding distraction, manual focusing is also much easier with a true view finder.

When they introduced Live View on DSLR, many of us, at first, thought that this would be the ticket, but as it turned out, the majority of us have stuck with the optical Viewfinder, it still a nice feature to have on a camera, and it is an essential one for shooting video, alas, it is not THE feature that we thought it could be.


For the benefit of explaining to the OP, I think there's two reasons for that - one is focusing speed/quality, and the other is 'ergonomics' or user interaction with the camera.

On the first subject, compacts use contrast-detect AF as you know, and can do it pretty quickly because they've got small, integrated lenses that typically don't have much throw and typically have smaller apertures (higher f-numbers) so they've got bigger focal depth ranges to begin with. DSLR's can't (in general, see caveats below) do CDAF as fast. Plus, CDAF as a technique is just analyzing 'sharpness' accross a portion of a scene, and only tells you when you're "in" focus and (through continuous sensor data analysis as the focus motor is moving) whether moving a lens is increasing or decreasing that local contrast. For the most part it isn't predictive. Phase-detect AF used by most DLSR's almost immediately measures not just whether or not a particular point is in focus but by how far, so it can immediately instruct a lens jump to here, and then fine-tune with a quick subsequent measurement and instruction. But the PDAF module is located in the viewfinder tunnel, fed by the mirror, which flips up and out of the way to let the light hit the sensor during actual exposure.

Most cameras using "live view" these days just flip that mirror out of the way, and let the sensor see the light, which means the PDAF module gets zilch. They then switch to CDAF as the autofocus mechanism (analyzing the sensor data), and given that the lenses are larger and more varied, the CDAF isn't in general as 'fast' as it can be on compact. Your history is a little unique though: the Olympus E330 was the first DLSR with live-view and also one of the few that did it different: the rear screen LV in that camera isn't provided by the main sensor but by an auxilliary display sensor that received light split off of the optical VF path, while the PDAF module was still active (the mirror was still down). Only when taking a shot did the mirror move. So the E330 had 'live view' and PDAF. Later Olympus DSLR's elminated this (too expensive and costs too much light in the optical VF to satisfy "serious" photographers, I guess)* and went back to CDAF and main sensor-provided live view. Sony's DSLR's sort of adopted something similar to the original E330 technique for a little while but with an optional secondary mirror tilt that would let the light bouncing from the mirror feed either a secondary sensor (for live view) or the optical viewfinder, but not both at the same time. I believe in either case though the PDAF module still got light. And of course the newer Sony SLT's are full-time "live view" since the transluscent mirror approach always allows both main sensor illumination and PDAF module illumination.

Since then mirrorless has come out, and a lot of advances especially from Panasonic and Olympus on CDAF speed such that it nearly rivals PDAF (even beats poorly-done PDAF in many cases). If you switch from your present E330, but still choose to shoot using the rear screen, keep in mind that means you're losing that semi-unique "live view" implementation and going to CDAF autofocus (mirrorless, or most DSLR's in "live view" mode), with the Sony exception.

On the second topic - focusing on the rear screen (with your eyes I mean) is difficult as it means you're dealing with ambient light and reflections masking your view, plus having to 'accomodate' focusing on something close to you. This gets harder on the eyes as you get older. And, it's hard to judge even if you can see the rear screen well whether critical fine focus is being displayed - the LCDs have lower pixel resolution than the sensor does. Most DLSR shooters prefer to use the actual camera's viewfinder (even without an external VF attachment) because when you look at the sceen in the viewfinder your eyes are 'focusing' on the scene as if you were looking at it normally, at distance, so the 'accomodation' issue for those of us who now need bifocals is gone. As you lift your eye from the viewfinder to look at the real scene, you're not having to shift your focus from near to far and back, it's far easier on the bioprocessed optics. Posted Image And, although it can be a bit awkward to squash your mask up against the housing, the view through the VF is a lot clearer (ambient light is blocked) and easier to judge the actual optics of the camera's current focal plane with. So if you do go DSLR, for the most part, you might want to assume that will also mean you'll be better off switching your shooting style to using that viewfinder like you would most of the time out of the housing.

Hope this helps - sorry to be longwinded.

[*Footnote: I had my E330 as my first DSLR in part because I was sold on the idea of 'live view' as a way to keep PDAF underwater and yet use the rear screen to shoot; it was my first foray away from compact cameras in general, much less underwater. I didn't like the idea of smooshing my face against the camera and ignoring surroundings (less experienced diver, plus I didn't yet need the bifocals). As a result when I later upgraded to an E30 and lost this feature - I found I just stopped using live view above water, and never bothered to house the E30. Frankly, it kind of soured me on Olympus although in many other ways I still loved the E30, and loved the Zuiko lenses. They just killed off what I thought of as groundbreaking, industry-unique liveview.

I muddled around a while before realizing the Sony's were doing more what I'd personally 'liked' with their SLT's and switched to that, and I'm back to using liveview above water for all sorts of wacky viewpoints (articulating LCD plus liveview with good fast focus performance lets you do all sorts of framing you can't do with your eye against the viewfinder). But even though I've gone to this Sony a55 underwater...my time with the E30 taught me a lot more use of the actual optical VF, I've become a more comfortable diver re: task loading my buddy and gauge and surroundings-awareness with camera attention, and my eye changes over the years have resulted in me using the viewfinder underwater vs. the rear screen.

I've come full-circle in the sense of having the chance at pretty good AF performance capability with the rear screen, but still preferring to use the VF tunnel to help me actually judge the focus and perform the framing. Seems like a contradiction, eh? :D ]


#313123 Pelican Case for Dome Port

Posted by rtrski on 19 July 2012 - 10:15 AM

A lot of people just get some sort of tupperware or 'cake pan' to hold the port, and pad the inside with a towel where it might contact the dome face. I know with an extension this might have to get pretty deep, but you can detach the extension and pack separately (and pack a plastic-handled strap wrench) with less space than leaving it assembled.

I have just been wrapping domes up in a piece of old wetsuit and strapping bungies around to hold it on, then stuffing it in the middle of my checked bag with the dive gear. So far...so good....but it hasn't travelled on a lot of trips with me overall.


(Is it just me or is there a lot of weirdness with font size when replying in the new Wetpixel??)


#312685 Anyone want to build their own (relatively) inexpensive ROV?

Posted by rtrski on 12 July 2012 - 05:22 PM

Hope no one minds me posting a Kickstarter that I thought was of interest. No, I'm not related to them in any way, just happened across it searching for Technology/photography/camera type keywords.

http://www.kickstart...ot?ref=category


#294508 Microflash to fire optical strobes without using camera's flash

Posted by rtrski on 05 November 2011 - 11:13 AM

Well, my LED trigger flash circuit project is finished, including the fiberoptic cable and mounting to both the z240 and the Ikelite housing.

Full photo log of the flash development is here. Best viewed as slideshow. Hit 'pause' at the bottom left, hit the 'show info' button at the top right to get the per-picture text info, and then continue thru images at your leisure.

http://www.flickr.co...716388071/show/

Also for those who want to try their own, I'm providing my bill of materials and circuit board layout and other comments in a powerpoint file attached here for download (Zipped). It includes links to extra details about DIY circuit board etching using a laser printer to make the mask and household chemicals as the etchant vs. anything fancy. Also makes some fit test suggestions to help others get this done in less steps than I did.

The fiberoptic DIY cable has been posted in the DIY subforum, here: http://wetpixel.com/...t...st&p=294502

Looking forward to giving this a real workout in Dominica in January!!

Attached Files




#294502 DIY Fiber Optic Top Mount for Ikelite Housing

Posted by rtrski on 05 November 2011 - 08:03 AM

Well I finally got the project fully done and there's a photo log of sorts up at Flickr. Probably easiest to view as slideshow - hit pause right at the beginning, hit the "show info" button top right to get the descriptions superposed on the images, and then click thru at your leisure at the bottom.

http://www.flickr.co...933420885/show/

Ignoring the microflash (which I'll document in another set soon), I spent all of $25 to make this fiberoptic cable (and there's a lot left over since I bought 10' of the cable). Parts used are a 1/4-20 bolt, rubber flat gasket, a small chunk of plastic, some 2-part plastic fusion glue, a couple grades of automotive and normal sandpaper, a tiny piece of 1/8" ID (after heating) heatshrink tubing, and the plug that came with the z240 strobe in the first place.