A question for Olympus 300/2.8 users...

Discussion in 'Native Lenses' started by alex g, Nov 9, 2017.

  1. alex g

    alex g Mu-43 All-Pro Subscribing Member

    Mar 30, 2016
    New York / Bath
    I've been searching for a source of spare DFH-43 drop-in filter holders for this lens. I want to be able to quickly exchange different values of ND filter without having to unscrew/screw them in each time, but additional holders appear to be a rare commodity. It looks like Olympus did once sell them as accessories, at least in some territories, but haven't done so for some time.

    I'd be grateful for any input on this. Can anyone confirm if any of the commonly available filter holders from other manufacturers are compatible with the 300/2.8? I know that the Canon 52mm drop-in holder is too big, but perhaps one of the older Nikon, Sigma or Tamron holders might conceivably fit, or at least be modified to fit?

    Thanks!
     
  2. Jeffcs

    Jeffcs Mu-43 Veteran

    225
    Jan 20, 2017
    Toms River NJ
    Jeffrey Swank
    My Nikon "Drop-in" were 39mm filter thread
     
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  3. barry13

    barry13 Super Moderator; Photon Wrangler Subscribing Member

    Mar 7, 2014
    Southern California
    Barry
    Could they be 3-D printed, it do they need to be metal?
    Perhaps a machine shop?
     
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  4. alex g

    alex g Mu-43 All-Pro Subscribing Member

    Mar 30, 2016
    New York / Bath
    Right — I've seen used copies of those for sale online and noted them as possible substitute candidates. The Olympus lens comes with two different filter holders: one for a rotating CPL filter, and the other for plain ND or UV filters. Although the latter holder is designed for 43mm filters, the diameter of the actual glass of the CPL is only 33mm, which means that 39mm ND filters should work equally well, provided the frame is no thicker than 3mm. That just leaves the other critical dimensions:
    • the diameter of the lens barrel at the point whether the filter is located,
    • the width (along the lens axis) of the curved part of the holder which covers the opening in the barrel.
    @Jeffcs@Jeffcs — do you still have that Nikon 300/2.8 by any chance? If you do, would you mind measuring those dimensions for me, if it isn't too much of a pain to do so? Would save me sourcing a used holder only to find it doesn't fit...

    Nikon and Olympus evidently used different types of securing catch mechanisms, but that might be something that could be modified or hacked in some way.

    Yeah, I've wondered about that too. I'm not convinced that a 3d print would be either strong enough or smooth enough on the surface which presses onto the lens barrel, which has a thin rubber seal on it to keep the elements away from the elements, so to speak, not to mention stray light. (Pulling the holder out in the first place is obviously going to put a big hole in the weathersealing strategy, but it's doable if you choose your moment and are quick about it).

    I think a machine shop might be a better option, but I'm a bit nervous of how much it's likely to cost to have three copies made — to my unpracticed eye it looks like it could be a deceptively time-consuming shape to achieve using a traditional lathe and milling machine, but maybe CNC tools have changed that, I don't know. I'd be glad of any informed opinions in this regard. The design could probably be simplified without sacrificing too much functionality, at the expense of a degree of visual neatness, but all the same, I reckon it's a non-trivial task.

    DFH-43.

    Anyway, I thought it might be worth asking around a bit first, just in case someone were to turn round and says something like: "Oh, yeah, the drop-in filter holder from a Tamron Something or Other fits perfectly if you file the end down a bit". Used filter holders from older lenses seem to go for around $50 online, which is a good bit less than a custom solution is likely to cost, I imagine.

    An alternative would be to use front filters instead, of course, but the front element is around 105mm in diameter, which makes it about 10mm too big for 4x4" filters, and I'd rather avoid having to fork out $2000 for a decent set of three 5x5" ND filters if I can possibly help it — not to mention the extra size, weight and cost of a proportionately larger matte box. 4x4" filters do just about work, but they clip the edges of the bokeh discs enough to be annoying once you've noticed it.
     
  5. Jeffcs

    Jeffcs Mu-43 Veteran

    225
    Jan 20, 2017
    Toms River NJ
    Jeffrey Swank
    @Jeffcs@Jeffcs — do you still have that Nikon 300/2.8 by any chance? If you do, would you mind measuring those dimensions for me, if it isn't too much of a pain to do so? Would save me sourcing a used holder only to find it doesn't fit...

    I only wish I still had the lens as I could give you a hand I only still have a set of color filters that fit into the holder and they are 39mm
    My copy was manual focus and when I went AF a lot of my MF lenses were sold or traded
     
  6. Mountain

    Mountain Mu-43 Veteran

    420
    Aug 2, 2013
    Colorado
    @alex g@alex g
    You might surprised by some higher end 3d printing processes. Checkout protolabs.com, they are my default for quick parts. They have cnc milling and turning as well, but like you said, it might be cost prohibitive for small quantities. They are a quick and simple type shop, so they dont do high precision, but their standard +-.005 tolerance is probably enough for your needs. If it's basically a thin plate, then you could also consider water jet as a potential process, likely to find cheaper vendors that way. Good luck.
     
  7. Mountain

    Mountain Mu-43 Veteran

    420
    Aug 2, 2013
    Colorado
    Out of curiosity, what are shooting with a 300mm lens that needs NDs?
     
  8. alex g

    alex g Mu-43 All-Pro Subscribing Member

    Mar 30, 2016
    New York / Bath
    Not to worry, thanks anyway!

    Thanks, that's useful input. I'll look into those options.

    Wildlife video.
     
  9. Mountain

    Mountain Mu-43 Veteran

    420
    Aug 2, 2013
    Colorado
    That makes sense, I never think in terms of 1/48 or 1/60 ss. Pretty hard to do at f/2.8 I suppose.
     
  10. retiredfromlife

    retiredfromlife Mu-43 All-Pro

    May 15, 2016
    Sydney, Australia
    [/QUOTE]
    I think a machine shop might be a better option, but I'm a bit nervous of how much it's likely to cost to have three copies made — to my unpracticed eye it looks like it could be a deceptively time-consuming shape to achieve using a traditional lathe and milling machine, but maybe CNC tools have changed that, I don't know. I'd be glad of any informed opinions in this regard. The design could probably be simplified without sacrificing too much functionality, at the expense of a degree of visual neatness, but all the same, I reckon it's a non-trivial task.[/QUOTE]

    ------------Quote separation did not work--------------
    I know the hourly rate the machine shop charges where I work. Just the cost of drawing it so it could be used for CNC would be prohibitive.
    Unless you know someone you could buy a new system for what it may cost to get a few of these machined.
     
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  11. alex g

    alex g Mu-43 All-Pro Subscribing Member

    Mar 30, 2016
    New York / Bath
    Definitely, especially if you want to keep the aperture open, depending on the time of day, of course. It's the speed with which light levels change at dawn and dusk (especially towards the equator) which make it all the more desirable to be able to change ND filters as quickly as possible so as to maximize the limited time available for shooting during those prime times for both wildlife activity and dramatic lighting. No time to be fighting with a jammed filter thread. Dedicated video cameras often address the issue by having ND filter wheels built into them (or, just recently, LCD-based non-polarizing optical variable ND filters), and there are a few companies offering lens adaptors which feature some form of ND control, but so far there are no clever alternatives available for DSLR/mirrorless video shooters using system lenses. In principle, it would be possible to hack an MMF-3 4/3 to µ43 adapter to accept drop in filters (possible in the sense that there is sufficient space available within the adapter to accomodate one), thereby providing a solution for users of 4/3 glass, but I imagine that the companies which make such adapters would be unlikely to consider the demand for one to be sufficient to make it worthwhile for them to do so.

    MMF-3 and DFH-43.


    Right, that's what I feared. Out of interest, do you mind saying what a typical hourly rate is for such work?

    (Btw, your quote separation didn't work because of the presence of the forward slash in the first format command. "QUOTE" opens a quote and "/QUOTE" closes it. :)
     
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  12. retiredfromlife

    retiredfromlife Mu-43 All-Pro

    May 15, 2016
    Sydney, Australia
    For jobbing work IE one off's the rate can be between $70.00 to $90.00 per hour. Small organisations probably charge less but often do not cover maintenance and replacement of equipment which causes them problems down the line.

    As soon as you talk volume the prices come right down, Often setup times are as much as a small job. But with jobs like filter holders design work may be needed. Unfortunately I do not know what drafting services cost. If you had a sample filter holder a draftsman could measure and draw it, but if you had no sample only a photo an engineer may need to design it first. One can just imagine the cost of that.
     
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  13. alex g

    alex g Mu-43 All-Pro Subscribing Member

    Mar 30, 2016
    New York / Bath
    Interesting, thanks. As it happens, I have some drafting experience myself, so I think I could probably put a DXF file together in Cadintosh. If it turns out that there are no readily available substitute holders out there, I'll try to find a local shop that might be interested in the project.
     
  14. Reflector

    Reflector Mu-43 Top Veteran

    760
    Aug 31, 2013
    If you're willing to commit time to this: You don't need to make a 1:1 holder if you're willing to give up "some" functionality in regards to the design.

    Instead of having what looks like the active locking mechanism on the holder, you could simplify the design a little so it functions as a simple drop in holder. Just don't turn the lens upside down with the holder inside.

    3D printing that? Don't print it in one piece, simplify the design and work with the pieces in an optimized manner so you're making it a "designed for addictive manufacturing" part. With what I can see from those photos you could get away with 2-3 pieces, the round section that would mate to the lens barrel and the plate that holds the filter. Maybe you'd want to have a third piece that is printed in a different orientation to take advantage of layer resolution vs smoothness of the print to handle the transition between the flat plate and the barrel piece.

    If you are 3D printing that, there's ways to anneal plastics (Specifically PLA, one of the common types for 3D printing) to make them extremely rigid and temperature resistant. We're talking about stiff past 100C for (as far as I can tell: short) durations.

    And for threads? You don't necessarily need to print those if you have a bunch of filters you'll keep in the holders. The metal threads in the filter will form relative threads in the plastic from deformation when you press fit it. You could print the threads, but it is time consuming and they won't be as smooth as actual metal threads (Or lack some holding strength... But you're not going to be reefing on this little filter holder are you?)

    Worst case scenario: Pick up a really, really good Variable ND and get ready to deal with pulling the filter holder out to adjust it. I have one for my Tokina that starts at 4 stops and they seem to be good all the way up to 10 and a bit more. No VND artifacts (The X/corner darkening/weirdness) unless I turn it past 11.

    Bonus point: If you go with the last point made above, you can have matched boxes to hold your filter holder with filter designed and made for them.
     
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  15. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    It becomes very easy to make if If you forego the lock and go with a drop in solution. You wouldn't really have to worry about rotating the lens if you throw in a rubber band or velcro strap...

    Personally I would use a laser cutter to cut shapes, one would be a rectangle and the other a flat section of the correct size for filter to mount in. Heat the first up until it becomes semi fluid and mold it over the bottom of the lens to fit the curve, then glue them together (ABS welds nicely with just acetone). Rather than attempting to print threads it would be much easier to buy a step down or step up ring, cut the unneeded threads off, and glue it into the plastic, Or even some cheap 43mm filters. A bench grinder would also clean things up a bit pretty easily.

    3mm ABS would probably do it nicely and is cheap and always on hand (commonly used for vacuum forming), it would need some hand finishing as it doesn't cut as cleanly as other plastics (it tends to slightly mushroom on the edges). Acrylic is probably too fragile (it shatters easily). If you want to be fancy it's not much harder to use aluminum sheet, however it's harder to join together (not really hard, it just requires a MIG welder rather than acetone).

    The advantage of a laser cutter over 3d printing is you're only dealing in two dimensions and a basic vector graphic is much easier to make, YMMV.
     
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  16. Reflector

    Reflector Mu-43 Top Veteran

    760
    Aug 31, 2013
    E-M1II EVF Round Magnifier Adapter.
    But if you're willing to go all the way and actually design something from scratch that's intended for additive manufacturing... You could always put your own locking mechanism in.

    The eyecup magnifier adapter I made here is a semi locking or at least a "self locking" design. I have an intermediate piece that latches onto the E-M1II's eyecup rails from below and the eyecup adapter slides in from above. The intermediate piece has two extensions on the top that help hold it against the rails and those are slightly bent outwards by the rail. When the adapter piece is pushed in it causes those to slightly engage against the inside surface of the adapter, making it hard to remove unintentionally. I had a previous design that slotted in from above but it didn't have any locking features and it started to get loose after a while.

    So this becomes a "how much time do you want to spend on this" question if you have your own modelling software and/or access to a 3D printer or any means of fabrication.

    Looking at that Olympus adapter, you could probably get away with woodworking if you felt like it. You could have the plate be a dovetailed/T slotted piece that slides out of the round section.
     
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  17. alex g

    alex g Mu-43 All-Pro Subscribing Member

    Mar 30, 2016
    New York / Bath
    To be honest I'd rather adapt an existing holder from another manufacturer, if there is one that is known to fit, which was the original question. But thanks for all the input anyway!
     
  18. SVQuant

    SVQuant Mu-43 Hall of Famer

    Sep 20, 2015
    SF Bay Area, California, USA
    Sameer
    You may have seen this one already, but the Tamron in this listing looks pretty close in size to your image and takes 43mm filters. May be worth making an offer to try the experiment?
    Tamron drop-in 43mm Filter Holder for SP 300mm /2.8 Telephoto Lens | eBay.
     
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  19. alex g

    alex g Mu-43 All-Pro Subscribing Member

    Mar 30, 2016
    New York / Bath
    Well-spotted Sameer, thanks! I had in fact just seen that listing and have made an offer, so we'll see what happens... I have a suspicion that the barrel diameter may be a little smaller than the Olympus, but it's worth a try!
     
  20. SVQuant

    SVQuant Mu-43 Hall of Famer

    Sep 20, 2015
    SF Bay Area, California, USA
    Sameer
    You are welcome. The holder part appears to be a little slimmer, but my guess would be that you could glue a little spacer to fix that.

    BTW, I asked my daughter (she runs the shop for her high school robotics team) if she could fabricate the holder using their tools and she thought that it would be pretty easy if you had the CAD done. They would do it for a reasonable sum, too! If you are looking to sponsor a high school robotics team, give me a holler :)
     
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