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 Replies: 20 / Views: 4,614 |
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Pillar of the Community
United States
4038 Posts |
I'm always looking for good deals on high quality optics, and I have found another "ringer" to alert you all to: the Bausch & Lomb 10x 0.25 16mm. In general I have not found B&L microscope objectives to be particularly good, at least the lower power ones. So when I bought this B&L 10x it was with modest expectations. But for $12 shipped, I could not pass up the opportunity. It turns out this objective is indeed very good, and is sharp out to the corners of the APS-C sensor. It also has excellent working distance, making the subject very easy to light. Best of all, it is very available on ebay for peanuts! One seller has 120 NOS objectives for sale at $25 each, so there should not be a shortage of supply. For comparison, I tested my Nikon M10 0.25, my best 10x objective, in the same lighting situation. The Nikon requires a longer extension, so I had to adjust the bellows between these two, and I was not very careful about matching the magnification, but they are not too far off. I did a simple 6-image stack on both, which is actually not sufficient but will give you an idea of what the objectives can achieve. Here are the comparison images: B&L 10x  Nikon 10x  |
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Valued Member
United States
403 Posts |
Many thanks for the tip! I've been struggling with an AmScope PA4X and needed a good&cheap upgrade. It's ordered and on the way! |
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Pillar of the Community
United States
9395 Posts |
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...It's ordered and on the way! I guess that explains why the ebay seller is down to 119 left. I wonder what the actual tube length is for these? Usually the specified tube lengths are 160mm or 210mm, meaning the real tube length with a camera is 150mm or 200mm. These have a specified tube length of 215mm. I wonder how do these objectives compare to the modern infinite-corrected ones like the Mitutoyo 10x/0.28? |
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Valued Member
United States
441 Posts |
Will the aforementioned objectives fit the M42 RMS adapter used with the <$400 setup? How can one tell when looking at objectives if the thread is the correct size for the adapter? Thanks.
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Pillar of the Community
 United States
4038 Posts |
I've never tested a Mitutoyo 10x Plan Apo, so can't tell you, but I do expect them to be sharper. A problem though, especially at these higher (relatively) magnifications is the depth of field. The Mit10x will require significantly more shots in the stack, with smaller step sizes, than the B&L. Most folks don't have facilities for lots of 5um steps, so this make the higher NA problematic. Even with the B&L you need to have consistent 10um steps to get a full-resolution image, and this is on the edge of the capability of most equipment. You can of course automate and achieve 1-2um consistent steps, but the cost of those setups sort of trumps the need for low cost objectives!
Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
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Pillar of the Community
United States
4038 Posts |
Quote:
Will the aforementioned objectives fit the M42 RMS adapter used with the <$400 setup? How can one tell when looking at objectives if the thread is the correct size for the adapter? Thanks. Yes, they are RMS objectives. 90% of all objectives (maybe 99%) are RMS. Only a few specialized objectives (such as the above mentioned Mitutoyo) have different threadings. |
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Valued Member
United States
71 Posts |
What was the working distance of this B&L microscope objective when you took the pictures?
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Pillar of the Community
United States
4038 Posts |
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Pillar of the Community
United States
949 Posts |
Please forgive the newbie (me) who has not yet figured out how to search the forum very well. How does one make use of an objective lens for coin photography? Are you shooting through the microscope, or does the objective lens mount to your camera somehow? Either way, I assume the field of view is quite small.
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Pillar of the Community
2087 Posts |
I mount microscope objectives on a bellows, other people use extension rings. This requires an adapter; usually RMS to whatever mount the extension rings Or bellows are. I have some generic microscope objectives and they are designed for specific extension distances which are indicated on the objectives. I just set the bellows to that distance. Yes the area you see is very small but I find all the objectives I have will produce an image that will cover the cameras sensor
Edited by austrokiwi
04/12/2016 1:50 pm
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Pillar of the Community
United States
949 Posts |
Thank you austrokiwi, I am looking into this now too. Apparently this is part of the move toward image stacking that got hot with this group starting back in January. Quote:
Even with the B&L you need to have consistent 10um steps to get a full-resolution image, and this is on the edge of the capability of most equipment. You can of course automate and achieve 1-2um consistent steps, but the cost of those setups sort of trumps the need for low cost objectives! All this may be obvious to you guys, but I need help getting into it. Thank you for your patience. @rmpsrpms Is this incremental adjustment something one can do well manually or does it require a special tool? Are you using the Helicon focus system or the Zerene Stacker system (manually)? Do you otherwise recommend/use the Cognisys StackShot? Edited by lrbguy
04/12/2016 5:13 pm
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Pillar of the Community
United States
4038 Posts |
I use a custom-built system similar to the StackShot. I've heard good things about StackShot so would have no issue recommending one. However, you don't absolutely need such an elaborate system unless you're doing a lot of stacking, or if you do "deep" stacks with many images (>10). If you want to stack manually, and will be doing it for coins (which typically require <10 images), then you might just consider getting a manual Z-stage. I use one of these for full-coin photography for fine focusing: http://www.ebay.com/itm/NEW-Z-axis-...AOSwewJTnwnT This stage has a micrometer control that gives 10um increments, which is sufficient for 10x magnification. If you're careful you can even do 5um half-steps. I process the image stacks with Helicon Focus. |
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Pillar of the Community
2087 Posts |
I use The stack-shot but starting out manual stacking can work, but as already pointed out getting fine consistent movements is an issue. You can buy a Z stage with a micrometer( usually expensive) or look for a parts Microscope that has a fine adjustment nob for the focusing stage. You will need to remove the objective head/turret with an angle grinder or similar tool. An Olympus CH2 or similar will work OK. You will then get the ability to adjust focus by amounts less than 10um Here is an example of the sort of microscope I mean ( note I think its too expensive with looking you should be able to find what you need for less than US$40.00) http://www.ebay.com/itm/Olympus-CH2...AOSwG-1W0mcMEdited by austrokiwi
04/12/2016 11:49 pm
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Valued Member
United States
441 Posts |
Do you have any pics of the stages attached to your rig to show how they would integrate with a bellows setup and rms objective? Need lots of pics.....visual learner is quicker for me.
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Pillar of the Community
2087 Posts |
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Do you have any pics of the stages attached to your rig to show how they would integrate with a bellows setup and rms objective? Will post pictures of bellows set up later. Here is an old picture that includes the microscope I modified to be a focusing stage. instead of moving the camera the coin is moved for stacking  Edited by austrokiwi
04/13/2016 02:40 am
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Valued Member
United States
441 Posts |
Very intricate setup. I assume the stage is mounted to the baseplate and can move vertically/horizontally in minute amounts, correct? How do you control how much the stage moves..micrometer, computer?
Do you have any coin pics using this system? This process is very cool!
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Replies: 20 / Views: 4,614 |
Posted 04/10/2016 5:58 pm
