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PostPosted: Mon Feb 18, 2019 8:52 pm 
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Hi Doron,
your USB camera does really well and I'm sure you will have fun with it. For web resolution and documentary work the very best camera solutions are a massive overkill and much of their capability doesn't show. On your GFL the USB cam does astonishingly well in web resolution but I'm sure that your Canon would win by far when critical obects at high resolutions were the task. But only with you stage micrometer pictures this slowly starts to show. A very good result for this relatively inexpensive camera.
I have more than one microscope and I'm quite happy with my portable camera solutions with Pentax Q and Nikon 1J5 because I can use them on the very microscope I use at this moment.

Can you post a link to where you bought the camera so anybody who needs one can buy the good one right away?

This evening I played with something completely different: A Zeiss Photomikroskop I with built in 35mm camera! In 1955 it was the first electronically controlled camera of the world, not pocketable though :lol: . The film transport is spring powered.

Bob


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PostPosted: Mon Feb 18, 2019 9:02 pm 
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microBob wrote:
...

Camera vendor: https://www.ebay.com/itm/5MP-USB-CMOS-C ... 2749.l2649
But if there is a dead pixel - I take no responsibility... :oops:

You play with a Photomicroskop and a 35mm film camera ? and process the film and print on paper ?? wow! how fortunate I am to enjoy photography without film !

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Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo


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PostPosted: Mon Feb 18, 2019 9:18 pm 
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MichaelG. wrote:
Hobbyst46 wrote:
3. There is at least one fixed alien black dot on all photos (e.g. circled in red in photo no.4). This dot originates from the camera, not the scope. I cleaned the lens thoroughly, but the dot stays. Perhaps it is dust on the sensor

Comments are welcome.

Having suffered my fair share of dusty sensors ... I would say it's more likely that you have a dead pixel there.

... Could you let us see a crop of that small region please ?

MichaelG.
.
.
P.S. I was looking at this earlier today:
https://www.lmscope.com/en/Stereomikroskope_in_der_Fotodokumendation_en.html
The suggestion of tilting the specimen, for single camera use on a Greenough, seems very logical.

Thanks for the link - I will read it.
In the meantime, I am afraid that your diagnosis of the black dot is correct, anyway here are two slightly different crops of it:
Oops - these came out tiny! what do it do to make them full size pictures ?


Attachments:
suspected dead pixel.jpg
suspected dead pixel.jpg [ 1.07 KiB | Viewed 1578 times ]
same suspected dead pixel.jpg
same suspected dead pixel.jpg [ 810 Bytes | Viewed 1578 times ]

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PostPosted: Mon Feb 18, 2019 9:44 pm 
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Location: NorthWest England
Hobbyst46 wrote:
In the meantime, I am afraid that your diagnosis of the black dot is correct, anyway here are two slightly different crops of it:
Oops - these came out tiny! what do it do to make them full size pictures ?

Open the full image in Photoshop [or another editor] and zoom to 'actual pixels'
... select say a 200x200 pixel area containing the region of interest and export that as a new image.

That should do it.

MichaelG.
.
Edit: for info. I have just copied the larger of your two crops and the posted version only appears to be 38x38 pixels.

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Last edited by MichaelG. on Mon Feb 18, 2019 9:53 pm, edited 1 time in total.

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PostPosted: Mon Feb 18, 2019 9:53 pm 
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MichaelG. wrote:
Hobbyst46 wrote:
In the meantime, I am afraid that your diagnosis of the black dot is correct, anyway here are two slightly different crops of it:
Oops - these came out tiny! what do it do to make them full size pictures ?

Open the full image in Photoshop [or another editor] and zoom to 'actual pixels'
... select say a 200x200 pixel area containing the region of interest and export that as a new image.

That should do it.

MichaelG.
This is a 100X100 pixel region


Attachments:
dot region.jpg
dot region.jpg [ 616 Bytes | Viewed 1575 times ]

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PostPosted: Mon Feb 18, 2019 9:57 pm 
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Location: NorthWest England
Something is going amiss, here

Perhaps you could zoom-in and do a screen grab.
... or could you perhaps share the original image, and let me try ?

MichaelG.

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PostPosted: Mon Feb 18, 2019 10:24 pm 
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This is expansion and screen capture - is this OK?


Attachments:
suspected dead pixels.jpg
suspected dead pixels.jpg [ 6.75 KiB | Viewed 1571 times ]

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PostPosted: Mon Feb 18, 2019 10:59 pm 
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Location: NorthWest England
That's much better ... Thanks !!

What we need to ponder now, is what it represents
If it was a true, uncompressed image of one, or more, dead pixel[s] then each would be a hard-edged black block.

This image is [unsurprisingly] showing the result of 'processing' ... jpeg compression and maybe some interpolation.

Do you have any way of confirming the native resolution of the camera chip ?
... or, even better, of identifying the make & model.

For now ... it's time for me to 'sleep on it'

MichaelG.
.
Edit: I have just quickly checked the numbers, and am happy that the pixel size and pixel count are correct for a 5MP sensor of 1/2.5 dimensions.
... I will attempt to 'present my case' tomorrow.

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Last edited by MichaelG. on Mon Feb 18, 2019 11:23 pm, edited 1 time in total.

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PostPosted: Mon Feb 18, 2019 11:18 pm 
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Location: Cumbria, UK
Looks awfully like dirt on the sensor to me. Have you used a hand lens 'puffer' or had a look at the sensor (or it's covering filter) perhaps under a stereo 'scope or even with a hand-lens?

With the lens/optics unscrewed the camera body will look like this - the tiny sensor is clearly visible and I suspect that a mote of dust may be stuck to it, giving you the problem...
Attachment:
Capture.JPG
Capture.JPG [ 23.71 KiB | Viewed 1556 times ]


The optics should simply unscrew straight off of the front pf the camera, leaving the tiny sensor visible and easily reached if it needs a wipe or a puff of air from a hand 'puffer'. I personally would check this first.
If you suspect that it's dirt on the optics of the camera just loosen the screwed-in optics on the front of the camera body and turn it (the optics tube) a tiny bit relative to the camera's case. If the spot persists but is in a different position in the image the dirt is on the optics somewhere, if it stays in the same position it's on the sensor - easily removed in my experience of both a 2mp and a 5mp version of this camera that I have.

Your images really don't look like dead pixels to me, more like a dirt/dust particle...

John B.

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PostPosted: Tue Feb 19, 2019 11:01 am 
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mrsonchus wrote:
Looks awfully like dirt on the sensor to me. Have you used a hand lens 'puffer' or had a look at the sensor (or it's covering filter) perhaps under a stereo 'scope or even with a hand-lens?...Your images really don't look like dead pixels to me, more like a dirt/dust particle...
Bull's eye, John B.!
MichaelG wrote:
...

So - finding the bug quest
0. Puffed the front and back of the reducing lens (again!) - black dot persists.
1. Rotated the reducing lens relative to the camera - black dot persists.
2. Removed the reducing lens and inspected the camera - a few tiny dust(?) parts revealed. Puffed them away.
3. Black dot persists. A bug - dead pixel - in the camera?
4. There appears to be a filter, it is glued to the back side of a retaining thread ring. Luckily, although I do not have a pin spanner or compass, the retaining ring and attached filter were easy to unscrew, with a pointed-tip forceps. Took out the filter and puffed front and back on it.
5. Inspected the bare camera sensor chip through the stereoscope - looks nice and clean.
6. Puffed the chip without touching it, several times.
7. Reassembled the apparatus and back to the microscope.
Now what about the bug? Here is a real one (aphid) from a flower.
Black dot gone. So, it had been dust. Perhaps shaped as a pixel...
Thanks folks for the help!


Attachments:
Aphid on tissue paper, 15X.jpg
Aphid on tissue paper, 15X.jpg [ 321.49 KiB | Viewed 1545 times ]

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PostPosted: Tue Feb 19, 2019 11:20 am 
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Location: Cumbria, UK
Great news!
It so often seems to be the simplest explanation that I always go to the basics first with the ever-recurring mystery-specks on the image problem!

Very recently I had the same problem (for the 1000th time!) and so went through the usual suspects - that time the dust particle was on the dratted mirror of my Orthoplan. I was able to reach it easily enough through the light-port and observe through the eyepieces as I removed it - but at first glance it was quite mysterious as all the other elements that I dutifully rotated, puffered, contemplated etc came up OK....

Great feeling when the swine's gone though! Almost worth having it there in the first place! :D :D

Nicely-done old chap.

John B. :)

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PostPosted: Tue Feb 19, 2019 1:02 pm 
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Location: NorthWest England
I stand corrected ... and remain impressed !!

MichaelG.
.

Quote:
So - finding the bug quest

Last time I tried something similar ... all I acheived was to introduce more dust.
People who live on busy main roads need 'glove-boxes' for this sort of work :(
[one of the many projects on my list ]

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Last edited by MichaelG. on Tue Feb 19, 2019 1:09 pm, edited 1 time in total.

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PostPosted: Tue Feb 19, 2019 1:07 pm 
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MichaelG. wrote:
...
In fact, that was collaborative thinking at its best! Thanks! All possibilties were considered. Bravo this forum.

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PostPosted: Wed Feb 27, 2019 1:40 am 
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Posts: 73
Hi all. I'm a newbie. Will this inexpensive camera properly attach to a "PARFOCAL C-MOUNT ADAPTER FOR Spencer, AO, American Optical TRINOCULAR MICROSCOPE"?

https://www.ebay.com/itm/PARFOCAL-C-MOU ... 2749.l2648

Thanks in advance.


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PostPosted: Wed Feb 27, 2019 8:34 am 
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geo_man wrote:
Hi all. I'm a newbie. Will this inexpensive camera properly attach to a "PARFOCAL C-MOUNT ADAPTER FOR Spencer, AO, American Optical TRINOCULAR MICROSCOPE"?

https://www.ebay.com/itm/PARFOCAL-C-MOU ... 2749.l2648

Thanks in advance.

It appears that the bare camera would attach
... According to the ebay description, it has a 'C port'
https://www.ebay.com/itm/5MP-USB-CMOS-Camera-Microscope-Digital-Electronic-Eyepiece-w-0-5X-C-Mount-Lens/273451506194
But that would mean losing the 0.5x lens, and you would be putting a rather small sensor into place.

MichaelG.

.
https://en.m.wikipedia.org/wiki/Image_sensor_format
Note that the 'available' frame for C-mount is just a little smaller than the 4/3 format ... but this camera sensor is only 1/2.5"

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PostPosted: Wed Feb 27, 2019 10:13 am 
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Thanks a lot, that's what I suspected. Probably better for me to get a more expensive one that will allow the .5x lens to be included, like this one:

https://www.amazon.com/gp/product/B074R ... ATMF5A2V9Z

Any other suggestions welcome.


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PostPosted: Wed Feb 27, 2019 10:38 am 
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geo_man wrote:
Thanks a lot, that's what I suspected. Probably better for me to get a more expensive one that will allow the .5x lens to be included, like this one:

https://www.amazon.com/gp/product/B074R ... ATMF5A2V9Z

Any other suggestions welcome.
IMO, the price is determined not only by the presence of a reducing lens (which IMO is indispensable) but by the USB type (3.0 vs 2.0), brand name (of no importance IMO) and features - image file types, custom white balance etc. The sensor size and pixel size vs number of pixels are important as well and have been discussed. Sorry that I cannot recommend any specific model.

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