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Magnifying lens help needed pls.

Discussion in 'General Electronics Discussion' started by Terry01, Aug 5, 2017.

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  1. Terry01


    Jul 5, 2017
    I am looking to buy a 2nd hand camera lens to help me see the smaller components and use as a good general magnifying glass. My eyes are shot basically,I have MS and some days my eyes are really bad and I need good magnification. I wear glasses and have a magnifying glass. I used one a friend had one time and it was awesome! I didn't think to find out the spec of it. Does anyone know what would be best for this purpose?
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    Jan 21, 2010
    Try a 50mm lens with a maximum aperture of f/2 or better (better is a smaller number)
    Terry01 likes this.
  3. Terry01


    Jul 5, 2017
    Awesome! Thanks Steve,that's exactly the information I was looking for. :)
  4. kellys_eye


    Jun 25, 2010
    Other than a handheld magnifying glass I've got a webcam with a 'macro' lens that I use with my adjacent PC. The webcam is on a goose neck and has an LED light-ring.

    This works well when I need it but I have plans to fit a small camera directly to the rear of a 7-inch LCD screen, also on a goose neck arrangement to allow me to (sort of) look directly at the work place but through a magnified TV image.

    With modern circuitry becoming ever-smaller this is a problem a lot of people are coming across yet there isn't any 'real' solution on offer (apart from stereoscopic units that cost a fortune).
  5. Terry01


    Jul 5, 2017
    Yes the decent ones cost a fortune! If I was doing this day in day out 8 hours every day I would pay good money but for what I need it for its not practical. I've had a quick squint on eBay and can get one that matches Steve's info for £10-20! I have the goose neck magnifying glass on both my helping hands which helps. I just really need something to check joints good on things once I'm done and things like that. I'm still learning too so not 100% sure after I've finished soldering,its good to check! Its funny too how different solders leave different finishes when you really look at it close. Spending that wee bit extra defo gives better results than the 2 quid a mile stuff from China! I soon learned that and won't go back!
  6. hevans1944

    hevans1944 Hop - AC8NS

    Jun 21, 2012
    "Best" is relative to your purpose, in this case the ability to "see" smaller components. Whether you also need to use your hands to manipulate those components is also a consideration. I would recommend that you start with a good binocular stereo head-mounted magnifier. I use Donegan Optical's Optivisor with a 4 diopter pair of precision-ground crown opthalmic glass prismatic lenses. These provide a working distance of about six to ten inches and a magnification of approximately 2X. Your working distance and magnification will depend on how your eyes focus, but lenses are available in 2, 3, 4, 5, 7, and 10 diopter focal lengths, with nominal magnifications and working distances of 1.5X at 20", 1.75X at 14", 2X at 10", 2.5X at 8", 2.75X at 6", and 3.5X at 4" respectively. Notice the working distance decreases substantially as the magnification increases.

    I have personally found that a 4 or 7 diopter lens is about the most I can comfortably use while placing and soldering SMD components. A 10 diopter lens is useful for inspecting components, but the working distance is too small for comfortable use with my hands. I plan to purchase a used stereo zoom microscope, mounted on an adjustable boom arm, after I start doing serious SMD assemblies. I also want to try one of the el-cheapo digital microscopes that use a CCD imager and a small monitor (usually your PC monitor via a USB connection) for display. I suspect these may be difficult to use with good eye-hand coordination because they lack a stereo view with good depth of field, but at a hundred bux or so, it may be worth a try.

    Finally, ordinary drug store "reading" glasses are available in various diopters and are relatively inexpensive. What they are not is convenient to use, because you must either remove them or look over the top of them to see distant objects in focus. A flip-up, head-mounted, arrangement is better IMHO, but your mileage (or kilometers) may differ.

    If so inclined, with deep pockets, you can also purchase expensive wearable stereo optics with good magnification and depth of field for upwards of a thousand bux... maybe cheaper if imported from China. Surgeons and dentists use these for hands-free viewing while doing their thing to you. They look like space cadets or bug-eyed monsters while wearing them, but they do get the job done.
  7. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    Jan 21, 2010
    The use of a 50mm lens as a quick substitute for a loupe is an old photographers trick. It's not necessarily the best option, and it is more bulky and heavier than other solutions.

    50mm lenses are usually good for this purpose because (at least in the past) were often double gaussian lenses, and of symmetrical or near-symmetrical construction.

    A good f/1.2 50mm lens can weigh a substantial amount as it has a lot of glass in it.

    Whilst no one would argue that photographic lenses are better quality than a typical magnifying glass, it is worth noting that other than specially designed macro lenses (which are even larger and generally have a much smaller aperture) these lenses are not designed for close up work.
  8. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    Jan 21, 2010
    A 50mm lens is a 20 diopter lens (just to pull Hop's post into tighter focus)
  9. Externet


    Aug 24, 2009
    I suggest you forget about magnifying glasses/lenses, you may end hating it.
    Get a 'bullet' NTSC surveillance video camera, available cheap. Screw-in a 16mm lens.
    Get a NTSC to VGA video converter if your monitor/TV does not have composite video-in.
    Attach to a desk lamp that had the magnifying glass and lamp removed.

    Alternative : Get a desk magnifying lamp and attach the camera to it without beheading.
    Dolby bench.JPG
    Ignore most of the equipment on my bench: The bullet camera is on front of the left keyboard at the tip of a beheaded desk lamp, above the board. Click image above for larger one.
    The board on the blue mat is what you see on the center top monitor. Image is for very fine pitch ICs, gets magnified like 400 times. Even more if you use a larger monitor.
    There is like 4 inches clearance from the camera lens to the board; plenty to do rework, probe, solder.
    Instead of looking at the board, you look at the monitor while probing/soldering/inspecting.
    You slide the board on the bench to the area of interest, you do not move the camera. When done, the camera retracts away to where does not bother.
    The NTSC-to-VGA converter is nylon-tie attached to the base stem of the lamp (lower left).
    Has a switch that allows the monitor to go back for computing use.
    No need for extra illumination. And two free hands... and nothing in front of your head nor worn on your face...

    There is no better way that I could come up with in 10 years of use/trying to improve it.

    The lamp before beheading is like ---->
    Camera can be like ---->
    Lens can be like ---->
    Last edited: Aug 5, 2017
    bushtech and hevans1944 like this.
  10. BobK


    Jan 5, 2010
    Depends on what you want it for. For close inspection I bought a very inexpensive ($15?) jewelers loupe with 2 lenses (30x and 60x) and an LED light. This is way to much magnification for use in soldering, but to inspect the final result or to read the code on a 0604 resistor, it is great. I needed this, for example, when I just soldered an SSOP 0.65mm pitch IC (imagine 4 pins in the space on one on a DIP) and there was a short. It took that much magnification for me to see the solder bridge.

    For soldering I use a headband mounted dual fresnel lens magnifier.

    A 50mm camera lens would not be pretty much useless for either of those tasks.

  11. Terry01


    Jul 5, 2017
    All great info and food for thought for the future! The camera hooked into the TV is too serious for my level of work and amount of soldering I'll be doing. I plan on using the magnifying lens for identifying small components,checking work I've done and things like that. I'm still brand new with electronics,like BRAND NEW! The most I have to deal with right now is an eBay DIY kit or identifying parts on boards so I can check the data sheet and find out how and why about the part. Thank you very much everyone for taking the time to reply.
  12. BobK


    Jan 5, 2010
    Then I would suggest a jeweler's loupe, and preferably lighted.

    hevans1944 and (*steve*) like this.
  13. 73's de Edd

    73's de Edd

    Aug 21, 2015
    Sir Terry01 . . . . .

    I have the Bausch and Lomb rectangular . .~4x6 . . . in rectangular hand held magnifier unit with its little inset additional magnifier. I have two strengths of the jewelers eye loupes, I have ~ 3 inch diameter dual lens sets, pulled from previous big screen TVs of mine. I have the typical head set mounted dual flip down lenses inspection glasses.

    Any one or several of which, are being used for making out the fine-tiny printed on info on IC’s and parts.

    My major-MAJOR choice is the dual lens unit that screws in and out of the front of this surplus unit being shown below .
    The outer ring I grip it with, is about 2---2.5 inches diameter.

    Believe me . . . there are what would seem to be $250 . . . of fine lenses within this unit . . . . .and it’s for sure my main unit, just mentioned, is glass, as I dropped it once and fractured a very fine divot into it on an edge. No effect, since it was located in a non-critical extreme edge area.

    I also believe that ALL of the other 8 lenses were made of of PREMIUM Pyrex glass and NOT plastics / Lucites .

    Now hold on very tightly to brace your belly fat . . .and click on reference to:


    Clickee - clickee . . .

    73’s de Edd

  14. Bluejets


    Oct 5, 2014

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