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 Replies: 17 / Views: 4,006 |
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Moderator
 United States
23522 Posts |
With all the discussions we have about stereomicroscopes and USB 'scopes for rollsearching, I decided to find out how suitable one of our dSLR imaging systems is for the task. The chief worry is the camera's sensor overheating from continuous use.
My research has indicated that this isn't a problem. In Canon's case (I would assume Nikon to be similar), the sensor is protected by two layers of warning. The initial warning tells you to consider giving the camera a rest soon, and the second warning means the camera will imminently shut itself down to cool. In any event, the camera will protect itself and prevent you from overheating it.
Further, I found very few instances where this has actually happened, to include results from pro shooters who live in Live View for hours on end. Shooting continuous video was a problem - especially 7D's were noted to show it - but not still imaging using Live View.
A great help is to shoot with an AC Adaptor instead of the battery, which not only drains more quickly in Live View but generates heat.
So going forward, those of you already shooting with dSLR rigs should be perfectly fine using that system for roll searching. I will be recommending that going forward.
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Valued Member
United States
374 Posts |
Haven't done roll searching in a few months, but now you, and some filtering techniques I've seen at work have got me thinking again...
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Rest in Peace
United States
10625 Posts |
Dave, is the AC adapter you're using a CANON brand or are you using a made in china off brand?
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Moderator
 United States
23522 Posts |
I currently use the Canon-branded one. I have used generic adapters in the past with zero problems. Other have not been as lucky as I - rmpsrpms lost a camera to a bad adapter - so I'm hesitant to recommend anything but Canon (generically, the one with the same brand as your camera) despite my personal experience.
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Rest in Peace
United States
10625 Posts |
Yeah, I'm always wary about using the non-brand stuff. Thanks for the info.
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Pillar of the Community
United States
4038 Posts |
SD...what was your conclusion regarding roll searching in Live View? I have considered it myself several times but have never tried. I actually built a setup for someone to do just that, but he never completed the deal, so I may give it a try. For me, the question would be what magnification to use. I suppose the 100% view would allow you to view full-screen, then zoom in for details. The next issue would be depth of field. Microscopes are fairly low NA/small aperture, which gives reasonable DOF but not great sharpness. I would assume one of the reasons to view with the DSLR is to allow immediate imaging of whatever you find, so you would want to use large apertures to get sharp photos. But large apertures imply shallow DOF, so the viewing process would be more difficult, eg trying to keep the whole field in focus. I suppose you could use small aperture for viewing, then open the aperture if you want to take a picture. Live View screen will compensate for the light differences. I'm curious to hear what you found in the investigation...Ray
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Moderator
United States
23522 Posts |
Quote:
SD...what was your conclusion regarding roll searching in Live View? My conclusion is the equipment is protected well enough that safety isn't a concern, and it's unlikely the most dedicated roll-searchers will ever push that limit. A blanket "go ahead and do it this way" endorsement, with the caveat that doing it via battery power increases the heat load and potential for invoking safety routines so an adapter is recommended. I have a 2560x1440 monitor. It's easy for me to work in full-zoom Live View because with the biggest sensors I still see a substantial fraction of the 100% image. And those screens are usually IPS and very close to proper gamut and color calibration out of the box. My cheap Auria sure is. In that view, it's plain to me that even our normal full-coin settings do not have enough DoF to get the whole z-axis; all of my full coin shots (as you know, normally around 0.4x) even at f/8-11 are a decision where I want to hold the focus in the range of DoF. I hold it high for grading shots, and low towards the fields for emphasis on die cracks etc. The visual result is barely noticeable at posting size; usually only I know. So, it's a win-win. You have the brutal sharpness of bespoke lenses combined with the ability to instantly record something you like onscreen at a quality you can then post online, wherever in the available DoF you wish. With the lenses we use, on a screen as large as mine, even the out-of-focus parts are still darn near presentable. We are *so* picking nits with this stuff, and we sometimes lose sight of that. Even our failures are usually presentable. |
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Pillar of the Community
United States
4038 Posts |
I'm talking with a guy on another forum about building a setup for doing live searching like you describe. In the discussion I realized that an important aspect is the ability to "scan" the coin, or if you're doing full-coin viewing, to frame it in the screen. An XY table gives this functionality nicely. Interestingly, Leica/B&L built a setup that seems almost ideally suited to this. It is their "Video Microscope" system. You can see a picture of it in this ebay auction: http://www.ebay.com/itm/LEICA-1x-Pl...371243700847The auction is for an objective for use on this system, but it has a (poor) photo of the system itself. The system has an XYZ stage for the specimen, then a height-adjustable optics mount. I've been successful in mounting either a MonoZoom7 or a DSLR onto the optics mount, and this is what I'm thinking would be good for live searching. I'll be away for a week or so and will try to check in but may not be able to effectively from where I'm going...will check back with you next weekend...Ray |
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Moderator
United States
23522 Posts |
Quote:
I'll be away for a week or so and will try to check in but may not be able to effectively from where I'm going...will check back with you next weekend...Ray
Enjoy the trip; hopefully it's vacation and not work-oriented. Places where Internet access is difficult are becoming some of the best places.  |
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Pillar of the Community
United States
4038 Posts |
Nope, not vacation. Troubleshooting some problems a customer is having. I think I solved them yesterday, and will be here til Fri on-call in case they crop up again. Just gotta figure out what to do in Shenzhen next 3 days. I'll be in Hong Kong all day Saturday, and hope to go to some of the Camera shops, and of course buy my wife a few things. I tried today in the Shenzhen Dongmen district, but was not favorably impressed with my selection. I may go to the Huaqiang Electronic district tonight or tomorrow to see if they have photo goodies or other must-haves to take home. Anyway, this is the first time I've been here with so much time to kill, so any suggestions are welcome.
Back to the topic at hand...
I heard from a forum member that you demo'd a live view setup like you're discussing here at a Philly coin show. What hardware did you use? I think this thread, and the work you've done leading up to it, is generating a lot of interest as I now have two folks interested in setting up a live viewing rig. I am leaning toward the Leica stand for this, as it has integrated XYZ stage, but want to know what you've already shown to work.
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Moderator
United States
23522 Posts |
Quote:
I heard from a forum member that you demo'd a live view setup like you're discussing here at a Philly coin show. What hardware did you use? All I did in Philly was our usual setup, with the output cloned to a second monitor turned for public viewing. All that member was seeing is how we normally do things. And the only difference in this thread, of course, is that I'm verifying how continuously it can be done. For those reading - including that particular member - this is why we preach tethering. |
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Pillar of the Community
United States
4038 Posts |
Yeah, I've found that the Live Viewing on PC screen is pretty compelling for folks. I take my setup to coin club meetings and take pics for folks, and they love to watch the monitor as I frame the coin, focus, and shoot. It's like watching a video of your favorite coins! And as you say, that's just how the system works. We've gotten so used to it that maybe the novelty has worn off, but it is pretty cool and advanced stuff. Almost magical first time you see it.
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Moderator
United States
23522 Posts |
And, having seen it work, you're left wondering how anyone can settle for less. Especially, as is the case with Canon, when the software is free.
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Pillar of the Community
United States
1476 Posts |
So, do you have pictures of the rig? I'm using an AmScope stero microscope for searching for varities and such with a 10mp camera but for some reason the lag is aweful when viewing and zooming in and out. I wonder if it's the AmScope software? |
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Pillar of the Community
Canada
9162 Posts |
Dave what you had in Philly to what you are doing in this tread 'live view' what's the difference?
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Moderator
United States
23522 Posts |
The point is, guys, what I was doing there is exactly what we teach you to do with your Canon dSLR/bellows rigs. That's what it is. You hook your camera to the computer via USB, you run the camera with your mouse, and everything you need to see happens on your monitor. I don't even adjust the coin under the camera offscreen - I reach to my side and watch what I'm doing in front of me. That's it. The only thing I did in Philly was hook up a second monitor so the audience could watch me do it at the same time. And I ran it from a laptop instead of my home computer. This was what it looked like, with the monitor on the left facing the audience:  Not that I didn't bother blocking the overhead lights, or use any diffusion. What we do with these systems is so far ahead of what's necessary that, as I've said before, all of the tweaks we make for diffusion and stacking and such probably can't even be seen in images posted here on the forum. This stuff is that good. |
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Replies: 17 / Views: 4,006 |
Posted 04/09/2015 1:09 pm
