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 Post subject: Re: dino-lite digital microscopes?
PostPosted: Wed Jan 25, 2012 7:50 pm 
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But this thread is not about CAMERA lenses. Its about hooking a point and shoot digicam
to a microscope.

Everything you have said about camera lenses is explained by this statement in my post.
Quote:
The phenomenon of some lenses performing better when "stopped down one or two stops" follow from the practice of consumer lens makers leaving some extra uncorrected glass at the periphery so that the consumer can grab a shot in darker conditions. But if the lenses were to be sold for a critical scientific purpose they would not have settings that could open beyond where the corrections meet the desired specs.

I will concede if you wanted to quibble about it, that "one or two stops" occasionally is even more than that. But the above is still true. It just means that the outer parts of the lens aren't corrected and should not be used. (ie lens should be stopped down.)
It means that the f/2.8 lens that needs to be stopped to f/4 is really an f/4 lens. It is not adequately corrected at f/2.8.

It means that the purpose of the those uncorrected range is to be able to grab a less sharp image , in a lesser illuminated situation. That is not what we are trying to do here. We have plenty of light available. The microscope objective has no diaphragm.

But really good lenses. Like Zeiss Luminars (and their legion clones) , Wild M400 zooms , Microscope objectives, Apo process lenses , semiconductor industry step and repeat lenses (that print microcircuitry resists) and other printing lenses are never stopped down (unless you want to sacrifice resolution for depth of field) Many such diffraction limited lenses don't even have an adjustable iris. They either have none or a fixed "waterhouse" stop.
Stopping them down wastes their resolution potential.

After Brian proposed his experiement I couldn't stop myself from doing it. It took about 90 seconds to modify it for local conditions. In my desk is a Shutter mounted Rodenstock 105mm Ysaron. We discarded an old Polaroid MP3 bellows camera and I stuck this lens in my drawer. I opened the shutter and put a piece of white paper on my desk as a screen and formed a real image of the lit light fixture over my desk.

Doing all the things Brian mentioned did nothing except dim the image. Similarly closing the diaphragm down to f/32 only dimmed the image. In no case did it vignette nor change diameter. When ray bundles were stopped (with a sheet of opaque metal) the image dimmed and resolution was lost although just looking with my eyes you could not tell that much.

One thing that was remarkable was the extent to which you could obscure the rays and still have a visible image.




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Quote:
G4Lab wrote:
I might be able to do your experiment using my office at work.


Now that you've done the expt, would you agree the results are completely counter-intuitive? How many people would guess that the image doesn't change, except that brightness goes down?

So stopping a lens will not reduce vignetting. And, given that any camera lens nowadays is designed with a certain aberration tolerance in mind, stopping the lens will not improve any aberration.

The brightness decreases as the lens is covered, because the number of ray paths used to create the image is reduced. Reducing the number of ray paths is equivalent to reducing the numerical aperture. And reducing the numerical aperture reduces resolution.

Unfortunately, we don't notice the resolution reduction in the experiment, because our eyes are not sensitive enough to the small details.




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I've been shooting for 25yrs+ and in real life every single lens I own from 40yr+ old ones to brand new 2011 manufacture date

My grandfather owned the largest photo studio and camera store in Vienna(three locations). After escaping from the Nazis he opened a similar store in Santiago Chile(which he and my uncle operated). My mother escaped here and opened the first photo processing lab here in St.Louis(in 1941) that gave 24 hour turn around for people's Kodak moments. I began helping her in that darkroom about 57 years ago. My mother was also a photographer and when she decided to close her darkroom business had another career as a biological photographer and darkroom tech at Washington University Medical School. (consistently third best in the country, )
I learned professional photography literally at my mothers' knee and was prenatally exposed to darkroom chemicals.
There were always German cameras around when I was growing up and I talked one of my dad's friends who traveled to Japan for bidness, into bringing me back a Nikon F outfit about 1966 or so. I wonder if you were alive in 1966.

I don't need to look at any web references. I made it my business to understand how optics worked when I was in college. (It does occur to me that when I was in the sixth grade I did a very slipshod science fair project in which I took my mothers Ihagee 6x9 cm(sheet film) folding bellows camera with a Zeiss Tessar lens and compared it to the anatomy of a human eye running strings from one analogous component to the corresponding structure on the diagram of the eye. The project was housed in a carton that had been the delivery box for Eastman Kodak (rip great yellow father) printing papers. I got a crappy grade( a "C") on it because I slapped it together. I didn't like my teacher. :lol:)


Last edited by G4Lab on Wed Jan 25, 2012 8:44 pm, edited 3 times in total.

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 Post subject: Re: dino-lite digital microscopes?
PostPosted: Wed Jan 25, 2012 8:29 pm 
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Swishman wrote:
If this is true, please explain how real world usage is just the opposite then!? Seriously.


Here, you are saying physics of optics doesn't apply to the real world? Even after I've given a real-world experiment, very easy to do, that disproves some of your preconceptions. So there really isn't a starting point for discussion.


Last edited by Brian on Thu Jan 26, 2012 12:15 am, edited 1 time in total.

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 Post subject: Re: dino-lite digital microscopes?
PostPosted: Wed Jan 25, 2012 11:11 pm 
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Thank you very much people for the kind help you brought me all. Starting from here, you've given me more than enough tips and tricks so I can experiment further and see by myself how good my scope/cam setting can be at it.
I really enjoy this forum :)

If I can get my hands on some new interesting stones with nice inclusions, be sure that you'll see some more pics from me again!


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 Post subject: Re: dino-lite digital microscopes?
PostPosted: Thu Jan 26, 2012 1:35 am 
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Quote:
It means that the f/2.8 lens that needs to be stopped to f/4 is really an f/4 lens. It is not adequately corrected at f/2.8


Swish, here lies your answer to why some lenses perform better when not used wide open. Saying 'all lenses perform better when squeezed down a bit' is against all logic...


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 Post subject: Re: dino-lite digital microscopes?
PostPosted: Thu Jan 26, 2012 2:13 am 
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If you were attaching the camera directly to the microscope with out the lens of the camera between them, then lenses wouldn't matter. You'd be correct.

But the lens is in between here, so it does indeed matter.

Brian, the proof of my statements are in the links with real world pictures right there for the looking. Distinctly showing the lack of quality and fringing wide open yet it disappears or at least gets greatly better stopped down not to mention sharper. Your experiment won't tell me anything. You missed the point. The point that what I was stating does indeed work,I don't care how nor why, only that it does.

It doesn't matter if a lens is f/4 in reality, it's sold as whatever it is, we don't know actually. We only know what is told to us on its specifications by the manufacturer. If they misrepresented it, that's not my fault.

You both missed the entire gist of my post in the process of over analyzing things.

I use this exact setup, different scope and cameras(like 8 or so different ones), almost daily. What I stated is what I've found to work perfectly well in the last 8yrs+ of using the setup.

I wasn't discussing anything. Nor did I want to. I was trying to help a user with PROVEN methods that do indeed work, regardless of how nor exactly why. They work, that's all that I give a doodoo about. Lol. But I'm not going to be told that something doesn't work while I'm sitting here doing the exact thing and it is indeed working! I should have stated helping privately and not bothered publicly. Sane bs everytime, not worth it. Lol.

But hundreds of images of proof and data on hundreds of lenses and cameras is just plain incorrect I guess. Lol.

Tim, saying none perform this way is no different. I also never stated every lens, I stated "every lens I ever owned, big difference." Again, we only know what a lens is sold as. Current lenses that most people buy work like I stated, even L glass. The proof is in my links. But again, they're all incorrect and impossible as well. So why bother checking them.

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 Post subject: Re: dino-lite digital microscopes?
PostPosted: Thu Jan 26, 2012 2:39 pm 
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Asserting the same incorrect point repeatedly does not magically make it correct. :cry:


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 Post subject: Re: dino-lite digital microscopes?
PostPosted: Tue Feb 21, 2012 12:32 pm 
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ok, definately, I can't take good pics of small inclusions if I can't see on a large screen if the inclusions is correctly focused and correctly lit. In my present setting, the pics looks fine on the camera screen, but once I transfer it to my computer it almost always turns out to be either out of focus (to close or too far focused), or too bright, or too dark or whatever.

What are the different options to get a live image on a computer screen?
Do some digital camera allow taking pics while connected to the computer (my camera doesn't) or do you have to use special devices (such as the dinolite cams or else)?


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 Post subject: Re: dino-lite digital microscopes?
PostPosted: Tue Feb 21, 2012 1:44 pm 
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cascaillou wrote:
ok, definately, I can't take good pics of small inclusions if I can't see on a large screen if the inclusions is correctly focused and correctly lit. In my present setting, the pics looks fine on the camera screen, but once I transfer it to my computer it almost always turns out to be either out of focus (to close or too far focused), or too bright, or too dark or whatever.

What are the different options to get a live image on a computer screen?
Do some digital camera allow taking pics while connected to the computer (my camera doesn't) or do you have to use special devices (such as the dinolite cams or else)?

Hi, I happen to use a Canon dSLR that is 2 years old and it has the ability to see the photo on the screen before I complete the shot. It is my understanding that there are other manufacturer's of SLR's that have this capacity as well. With a little research I believe you may see your options.

Could try http://www.steves-digicams.com/ or http://www.dpreview.com

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 Post subject: Re: dino-lite digital microscopes?
PostPosted: Tue Feb 21, 2012 1:55 pm 
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Quote:
it has the ability to see the photo on the screen before I complete the shot.

is it a live computer image (meaning that it moves when you move the cam) or is it frozen?

By the way, how is that feature named (so I can check which cam have it and which don't)?

I hoped maybe there were some computer applications to enable this feature in my cam but it doesn't seem so. Bad luck mine doesn't have this feature because it's a pity that I would have to replace such a fine cam.


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 Post subject: Re: dino-lite digital microscopes?
PostPosted: Tue Feb 21, 2012 2:42 pm 
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cascaillou wrote:
Quote:
it has the ability to see the photo on the screen before I complete the shot.

is it a live computer image (meaning that it moves when you move the cam) or is it frozen?

By the way, how is that feature named (so I can check which cam have it and which don't)?

I hoped maybe there were some computer applications to enable this feature in my cam but it doesn't seem so. Bad luck mine doesn't have this feature because it's a pity that I would have to replace such a fine cam.

Hi,
It is referred to as 'live view' by Canon. But other manufacturers may refer to it with other descriptive names. It is 'live' as in when I move my hand, it moves on the screen as well. You may want to check through your feature list provided by the manufacturer to be certain it is not included. I state this as I was unaware that my model had the feature until 6 months after I was using it.

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 Post subject: Re: dino-lite digital microscopes?
PostPosted: Tue Feb 21, 2012 4:43 pm 
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my cam also has 'live view' but I think it refers to the ability to frame images in the camera lcd screen, and it doesn't necessarly means you can frame image in your computer screen. I don't know how they call this latest ability but I fear my cam doesn't have it (or I don't know how to turn it on)
Did you need to install a program on your computer to enable live computer screen view? (I mean some kind of player program). If not, what player program does the live view open in on your computer? (windows media player?)


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 Post subject: Re: dino-lite digital microscopes?
PostPosted: Tue Feb 21, 2012 6:35 pm 
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google eos utility for canon and controlmynikon for nikons...


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 Post subject: Re: dino-lite digital microscopes?
PostPosted: Tue Feb 21, 2012 8:05 pm 
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I think sony makes a program called 'Remote camera control', but it is not supposed to work with the model I own


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 Post subject: Re: dino-lite digital microscopes?
PostPosted: Thu Feb 23, 2012 3:04 am 
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I can vouch for ControlMyNikon. Excellent software, well worth the $20 it's currently selling for. And the developer is from Vancouver, BC (which I consider home) which is even better.

I've been using with with my D7000 for macro photography (of my gems, of course! :)). No more squinty hours trying to focus the bloody camera and ending up with hundreds of fuzzy pics. Using streaming Live View I can see the exact focus I need before snapping the shot.

And the developer is quick to respond to any questions, even if you're using the 14 day free trial. That experience itself was enough to make me pay the $20 for the program.

http://controlmynikon.com/cmn.html

And for the record, I'm just a satisfied customer who'd wants others to benefit from this excellent software.

-Allan

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 Post subject: Re: dino-lite digital microscopes?
PostPosted: Thu Feb 23, 2012 11:42 am 
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thanks for the feedback.
So I need a new camera despite mine works perfect, great :evil:
I'm still looking for a software that can monitor my cam (sony dsc-h3) but maybe it just doesn't exist as I couldn't find anything on the web (I also called sony and they don't know)


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