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First impressions of using achromats on the 45-175

Discussion in 'Native Lenses' started by gardenersassistant, Jun 29, 2012.

  1. I use four achromatic close-up lenses: Raynox 250, 150 and 202, and Canon 500D, to photograph mainly insects, spiders etc and small flowers. Used on a 45-200 lens on a G3 these capture scenes down to about 4mm wide.

    A few days ago I purchased a Panasonic 45-175 lens. It makes the close-up lenses much easier to use, especially the more powerful ones, and my early impression is that it is producing better and/or more pleasing image quality too. (I need to examine and post process more images to work out exactly what is going on – the story is not straightforward, but seems very promising thus far.)

    Given that it is also significantly lighter than the 45-200 (which matters to me because of the techniques I use), does not suffer from lens-creep (which matters to me because I sometimes shoot from above) and focuses very positively and quite fast, I am so far well pleased with the 45-175.
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  2. phdezra

    phdezra Mu-43 Stalker Subscribing Member

    Dec 6, 2011
    New York, NY
    Sample images to share?
  3. sLorenzi

    sLorenzi Mu-43 Top Veteran

    Sep 15, 2010
    Would like to see some samples too if it is possible for you. Thx.

    Sent from my BlackBerry 9000 using Tapatalk
  4. Thus far I have only uploaded images from my first short session in the garden on the day I received the lens (and after spending some time on tests to look for any evidence of the "double-image" problem, tests which failed fortunately). I got just over an hour in before rain stopped play (yet again).

    During that session I captured some images with all four achromats. With lowish light levels and a breeze, conditions were not too good for my type of photography (natural light, often small aperture for deep dof), especially for higher magnification shots, so I kept the camera on ISO 800 and used shutter speeds as slow as 1/10 sec. There was not much fauna in evidence, and the flies and spiders I did come across were all pretty small – MSN-202 type small in a couple of cases.

    Failure rates were, as is often the case with my approach, very high. Out of the 300 or so captures I ended up processing 18. They are at First images using achromats on 45-175 lens, 26 June 2012 - a set on Flickr). They are processed for viewing 900 pixels height - Flickr resizing may do odd things to the image quality and is best avoided if possible.

    I have a backlog of 2,000 or so images from the subsequent two days in the garden. So far I have only done a quick first cut which dispensed with about 1,400 of them to give an initial "long list" of 600 or so to work on. I have done quick processing on half a dozen or so to get a feel for what I have got there to work with. The next step is to start picking images out of the long list (promising ones and also some not so promising ones) and see how they respond to more considered processing.
  5. Here are some more examples.

    I processed 103 images from the day 1 long list of 337 images, and uploaded 90 of them to Flickr, here. These numbers are in the range of what I usually get with the 45-200, perhaps towards the top end of the range given the breezy conditions and low-ish light levels for a lot of the shots. As a result of the conditions all but the first two of the uploaded images are ISO 800, and shutter speeds went to as slow as 1/5 sec. The largest crop was this one (captured when the light was better), which (before being resized for the web) used 34% of the pixels in the original.

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    0429 43 2012_06_27 P1430785 PS1 Cr34LetDf7x30CuSL9 900hSS59x0.3 by gardenersassistant, on Flickr
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  6. mnhoj

    mnhoj There and back again and again Subscribing Member

    Dec 3, 2011
    Los Angeles
    John M
    Very nice.
  7. tdekany

    tdekany Mu-43 All-Pro

    Dec 8, 2011
    Very very nice. I'll check out your other pictures now....
  8. phdezra

    phdezra Mu-43 Stalker Subscribing Member

    Dec 6, 2011
    New York, NY
    Very nicely done. Could you describe your method a bit more specifically? Do you stack all the lenses on the 45-175 at once? If so, what order? Can you show a pic of the lens? What is the focussing distance? Thanks.

    Some really, really nice shots in your Flickr album. Love the insect work.
  9. My approach

    Thanks all for the kind and encouraging comments.

    OK. This turned into several posts! Hope some of this is useful.

    The following posts deal with:
    Places, times of day and achromats
    Capture techniques
    Using achromats
    Image selection and post processing
    For those who prefer photos to verbiage, here are a couple of pictures I captured yesterday with (probably) the Raynox 250 on (definitely) the 45-175 on my G3. For those (if any) who do wade through the following posts, some information about these images may give some perspective on some of the points discussed in the following posts.

    Colour-wise, detail-wise and dof-wise, this first one is good enough for my current standards and preferences (until someone points out some horrible feature I have missed completely!). It used ISO 800, f/22 and ½ sec exposure. It had very light and basic post processing, and no noise reduction.

    [Processed for viewing at 900 pixels high. The 900 pixel high version is available at Flickr by clicking on the long strange file name beneath the image, right clicking on the image you get to at Flickr and choosing "Original" from the pop-up menu.]

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    0430 11 2012_07_01 P1450877 PS1 CrLebDf7x30CuSL9 900hSS135x0.3 by gardenersassistant, on Flickr

    In contrast, I find this one less pleasing because of the loss of focus on the far end of the abdomen and the far wing. The capture settings were the same as for the previous one. The post processing was much the same too, except that in this case I used a bit of the compositional cheating mentioned in the post processing post below.

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    0430 07 2012_07_01 P1450873 PS1 CrWaDf7x30CuSL9 900hSS135x0.3 by gardenersassistant, on Flickr

    Incidentally the long exposure, on what was a very breezy afternoon, was only possible because the flower the fly had settled on was on the ground and sheltered by lots of surrounding vegetation from the breeze.

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    0430 06 2012_07_01 P1450870 PS1 Df7x30CuSL9 900hSS138x0.3 by gardenersassistant, on Flickr
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  10. Equipment

    Here is a picture of the 45-175 next to the 45-200.

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    Panasonic 45-175 and 45-200 by gardenersassistant, on Flickr

    There are pictures here of the gear I use for shooting close-ups.
    Macro set up - a set on Flickr

    Each of the four achromats has step rings taking it to 52mm, for use on the 45-200. The 45-175 has a 46mm filter size, so I now have a 46-52 step ring permanently attached to the 45-175. (Incidentally, I almost never change the lens – I have no primes and hardly ever use the 14-42 kit lens. I believe not changing lens helps keep pollen etc out of the camera.)

    Here is a picture of the 45-175 with Raynox 250 mounted. I have UV filters on all the achromats except the MSN-202, which does not have a filter thread.

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    Panasonic 45-175 with Raynox 250 by gardenersassistant, on Flickr

    I use a home-made LCD hood made of black thin card/thick paper.

    For hands-off shots I use a (wired) remote release.

    The camera is on a small “riser” which is attached to a focus rail. The riser is needed with the 45-200 because if the camera is attached directly to the focus rail the zoom ring touches the focus rail and can't be turned. The 45-175 has a smaller diameter, so I removed the riser because the camera tends to rotate on the riser with only gentle turning pressure from my hands (with my hands off, it stays in place). However, I quickly put the riser back again because the setup turned out to be awkward to use without it.

    The focus rail is on ball head, which is attached to the tripod arm, which is attached to the tripod's central column, which can be reversed. This setup allows me to set the camera up from almost ground level to higher than I can reach without standing on something.

    I don't use flash much, but I have built a home-made diffuser, and I also have a white-ish card which I can attached to the tripod using a bendy clamp thingy (Winberley Plamp). I use the card as a flash reflector and/or sunlight blocker.

    Various other bits and pieces as shown in the photos.

    Almost everything in the bag now lives inside freezer food bags, because the equipment bag spends most of the time on the ground and there is often dew or rain residue which seeps through the bag and makes the stuff inside damp.

    The camera in the separate bag next to the wellies with a silvery LCD hood on it is my SX10is bridge camera. For a while after getting the G3 I took that with me on sunny days so I could use it to grab shots of butterflies, dragonflies and damselflies without having to demount the G3 and disturb what might be a delicately set up arrangement capturing some smaller subject. I don't bother doing that now – the extra bag was one step too many in awkwardness. For similar reasons, I have stopped taking the diffuser with me – because of its shape the diffuser has to travel on the outside of my bag, and the kitchen towel on the diffuser is very easily torn by brambles etc (which are shoulder-height and higher on some of the sites I visit). Repairing the diffuser on-site was possible, but too much bother.
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  11. Places, times of day and achromats

    When I retired and got back into photography I spent several years taking photos mostly in our garden, using the Canon S3is bridge camera and then the Canon SX10 bridge camera. With these I used the Raynox 250, Raynox 150 and Canon 500D close-up lenses. We live a couple of hundred yards up a hillside from the edge of the Severn Estuary and so we get a lot of breeze, both on-shore breeze coming up the hillside and prevailing westerlies coming up the estuary from the Atlantic. Not ideal for close-ups.

    About a year ago I started visiting a local nature reserve, and they quite quickly gave me permits for several more of their sites. These are the Avon Wildlife Trust sites at Collection: Avon Wildlife Trust sites and events

    I keep my eye on the weather forecast and go to these sites on days when low wind speed is predicted. I have taken to getting up at 4am-ish and turning up at dawn, because there tends to be less breeze early in the morning (and sometimes completely still air for an hour or perhaps two – bliss). Also, snails and slugs are active at that time of day, in large numbers, and insects are inactive and can sometimes be found, perfectly still, and covered in dew.

    I will typically spend 5 to 7 hours on site and capture 600 – 1500 images.

    My other favoured time of day is late afternoon, when the light can have a special quality to it. I tend to mooch around in the garden at that time of day looking for light coming down through the foliage and pooling on flowers (my wife is a keen gardener). Sometimes as the foliage flutters you get constantly changing patterns of light and shade. These patterns change far too fast for me to see a nice one and capture it, so I sometimes take “play of light” sequences where I just keep shooting in the hope of capturing something interesting.

    Just a few days before purchasing the 45-175 I purchased a Raynox MSN-202. I will describe usage techniques in the next post, but for now here is some information for each of the achromats, on the 45-200 and the 45-175, set out as

    Lens, Diopters (“power”), working distance, scene width at maximum zoom/magnification, maximum magnification in terms of the G3 micro four thirds sensor, equivalent magnification for an APS-C (Canon, 22mm) sensor for a scene that width.

    EDIT: As posted these two sets of numbers were the wrong way round. They are now the correct way round. My apologies.


    Canon 500D, 2 diopters, 360mm, 40mm, 2.2:1, 1.8:1
    Raynox 150, 4.8 diopters, 160mm, 19mm, 1.1:1, 1:1.2
    Raynox 250, 8 diopters, 109mm, 12.5mm, 1:1.4, 1:1.8
    Raynox 202, 25 diopters, 32mm, 4.25mm, 1:4.2, 1:5.2


    Canon 500D, 2 diopters, 316mm, 35mm, 1.9:1, 1.6:1
    Raynox 150, 4.8 diopters, 160mm, 18mm, 1.1, 1:1.2
    Raynox 250, 8 diopters, 102mm, 12mm, 1:1.5, 1:1.8
    Raynox 202, 25 diopters, 32mm, 4.25mm, 1:4.2, 1:5.2

    The measurements are the best I could manage with a tape measure, and there are issues in coming up with a definitive working distance.

    The minimum scene width for each achromat overlaps the maximum scene width for the next one, and so with both the 45-200 and the 45-175 there is complete coverage down to about 4mm scene width. If my calculations are right, this is about the same scene width as you get with an MPE-65 (which goes to 1:5) on a Canon APS-C camera. (Not the same image quality, of course, but then again not the same price either.).

    I tend to use:

    • the 500D for flowers and large insects such as butterflies, dragonflies, damselflies and craneflies
    • the 150 for wasps, bees, beetles and big flies, slugs, snails and larger spiders, and small flowers and buds
    • the 250 for smaller flies and spiders
    • the 202 for the smallest flies and spiders, and other small things like aphids and springtails.
    I never stack the achromats.
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  12. Capture techniques

    There are various things I could do to get better clarity/colours/resolution of details, deeper dof etc – use a camera with a larger sensor, use RAW, use dedicated prime macro lenses, use flash more, use better flash arrangements, use lower ISOs, use faster shutter speeds, use larger apertures, use focus stacking, put subjects in the fridge to cool them down so they don't move so much, set up a well controlled scene and use bait to draw subjects into the scene. However, as well as having obvious advantages, there are downsides to each of these, and so what I describe here is the techniques that provide the trade-offs I am most comfortable with at the moment. Next week, next year, it may well be different.

    I always use JPEG. I use the Natural Photo Style with contrast, sharpness, saturation and noise reduction all turned down to their minimum of -2.

    I almost always have the camera on the tripod. (Exceptions – on brighter days chasing butterflies, bees in flight etc, with a decent shutter speed.)

    Where possible, I use a hands-off approach where I set up the shot, take my hands away, wait for the rig to settle and then use the remote shutter release to take shots. Image stabilisation is always off for these shots. Even in perfectly still air I take more than one shot with each setup. With a breeze, I take lots of shots.

    I keep my hands on the camera if I need to follow the subject as it wanders around or I simply can't get the framing how I want it (there is lots of flex in all the joints in the rig and where exactly it settles has a random factor to it that can be very frustrating, especially if at last you have it set up right and then the breeze moves the subject and it settles in a different position). I sometimes turn image stabilisation on for such hands-on shots, but I really don't know if this is a good thing, neutral, or a bad thing.

    I prefer to use a flippy, side-mounted LCD screen rather than a viewfinder. In fact, I never use the viewfinder for close-ups.

    I usually use autofocus, with a moveable focus box that I make as small as possible. I only use manual focus if I can't get what I want with autofocus, which is rare (e.g. sometimes with a spider on the other side of its web). I aim to place the focus box somewhere in the middle (back to front) of where I want the dof to fall. I prefer to get the (obviously to the eye) nearer parts of the subject somewhat in focus, but especially with e.g. insect legs that may simply not be possible.

    I prefer to get as much of my subject as I can in focus. When the subject is relatively close-up (occupying a middling to large proportion of the frame) I use the smallest aperture I have, f/22, to get the largest dof I can. This causes considerable loss of detail because of diffraction, but for the sizes of image that I produce (900 pixels high for on-screen viewing, and generally A4 for printing, occasionally 16 x 12 inches) I am content with the detail I get.

    Cropping a less magnified image can have the side-effect of giving greater dof around the subject than a more magnified, uncropped image covering the cropped area, but obviously there is a trade-off in loss of detail from the cropping.

    I prefer to use natural light as the main light source.

    Given my not using flash as the main light source, my use of small apertures and the often poor UK/early-morning/in-the-shade light levels, I often use slow exposures and/or high ISOs. I tend to use ISO 800 and then let the exposure be what it will.

    I have the camera set to multi-point metering. I set the exposure compensation so as to try to avoid blown (to white) highlights or blown (to wrong colour) channels. I tend to under-expose flowers, which often have light coloured petals, under-exposing by as much as two or sometimes more stops relative to what the camera advises. I tend to over-expose dark insects, by as much as one or occasionally more stops relative to the camera's advice. I set the exposure by eye from what I see on the LCD before the shot, and adjust the exposure if I see highlight “blinkies” on the captured image. I don't use the camera histogram.

    I sometimes use flash to even out the lighting and bring up the shadows in bright, contrasty light conditions. I have a Metz 58-AF2 flash which I may use direct for fill flash or may bounce off the white card. In some cases, for example with an insect on the underside of a leaf, I may need to use flash as the main light source. I have found the card on its bendy support rather more flexible in such cases than my home made diffuser (which is another reason for currently not taking the diffuser with me).

    Fill flash is generally used in brighter conditions, and the shutter speed may be above the G3's sync speed of 1/160 sec even if using the minimum ISO of 160. I use FPS (HSS) flash in these cases.
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  13. Using achromats

    Each achromat has a preferred “working distance” between the front of the lens and the subject. Each achromat has a range of lens to subject distances around the working distance for which you will be able to gain auto-focus. Outside of that range you cannot gain auto-focus (and presumably manual focus will be soft, increasingly so as you depart further from the preferred working distance).

    The usable range of lens to subject distance is:
    Large for the 500D, which is very easy to use;
    Middling for the 150, which is fairly easy to use;
    Rather smaller for the 250, which can make it quite difficult to use;
    Very small for the 202, which can make it extremely difficult to use.
    It is difficult to give a precise distance for the 202 because the distances are so small and the results are a bit variable, but at minimum zoom/magnification the 202 appears to gain auto-focus on the 45-175 only if it is between 29 and 32mm from the subject. That is, there is about a 3mm tolerance in the working distance. At maximum zoom/magnification this appears to be reduced to nearer to 2mm. Indeed, if you move more than 2 or 3 mm outside of this range then you simply won't see the subject, not even a faint out of focus hint of where it is. This can make it very difficult to even find the subject.

    The MSN-202 turned out to be ferociously difficult (for me at least) to use on the 45-200. With achromats you change the amount of magnification (and hence the framing/composition of the image) by altering the amount of zoom. Unfortunately, on the 45-200 the lens extends/contracts as you increase/decrease the amount of zoom, and this changes the distance to the subject. In fact, between maximum and minimum zoom the 45-200 extends/contracts about 35mm. So, once you have found the subject, if you want to reframe the image by changing the magnification then you have to go through the whole, difficult, adjust-the-zoom + find-the-subject+ adjust-the-working-distance-to- 32mm routine again. During my first session with the 202, using the 45-200, I did manage to get a few (very few) images, but the difficulty and frustration of it convinced me that using the 202 was going to be a very occasional thing.

    Another issue with the 45-200 is that with all of the achromats there is a lens-creep problem. My tripod lets me work at various crazy angles to get a line on subjects, including from directly above. The trouble is that with an achromat attached once you get somewhat close to the vertical the lens creeps down to its maximum extension/zoom, so you can't adjust the zoom to get the composition you want; you have to work at maximum zoom/magnification.

    In contrast, all the achromats work sweetly on the 45-175. The fixed length makes things much easier, to the extent that the MSN-202 instantly became just another lens in the kitbag rather than an exotic monster. And it is a joy with all the achromats being able to reframe from one end of the zoom range to the other without having any concern whatever about distances or moving the camera – it really lets you concentrate on composition etc. And no lens-creep either. I have done fully vertical top-down shots, with no problem.

    So, my approach with any of the achromats on the 45-175 is this.
    (I have Quick Autofocus on so the autofocus is working all the time. To conserve battery power I turn the camera off as soon as I stop taking photos, and until the next shot is roughly lined up. Even so, I have five batteries – two Panasonic and three third party - and often use three and sometimes four in a session, and once had started on the fifth.)
    • Put the camera half way or so between the front and the back of the focus rail.
    • Adjust the tripod so the camera is pointing in the right direction a bit further away than is needed for that achromat.
    • Turn the camera on.
    • Set the zoom/magnification to minimum (especially if using the 202).
    • Use the quick release on the focus rail and quickly slide the camera towards the subject until the auto-focus gains focus. (If necessary, and it is only ever necessary with the 202, use the fine adjustment screw on the focus rail to get the distance to where auto-focus can gain focus.)
    • Use the zoom to frame the shot.
    • Take hands off camera.
    • Watch LCD until all visible movement stops. (Well, in perfect conditions. If there is any breeze the subject may still be moving even if the camera isn't.)
    • Press remote shutter release. Repeatedly.
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  14. Image selection and post processing

    I use Faststone image viewer to run through the images very fast and copy to another directory all the ones that don't have glaring problems like being out of focus, having dof falling in the wrong, having impossible to deal with compositional problems etc. The resulting “long list” typically contains a quarter to a third of the captured images.

    I then work through that “long list” to pick out images to try processing, trying to pick out “the best of the bunch” for each scene/subject pose and then deciding if it is worth attempting to process. For reasons discussed in the next paragraph, this “try it or bin it” decision has become a bit more difficult with the 45-175.

    I used the same minimal (-2) camera settings for the 45-175 as the 45-200, and so the images don't look wonderful out of the camera, but the images from the 45-175 seem to come out of the camera even softer than those from the 45-200. This worried me initially, but I quickly discovered that they seem to respond to processing better than the 45-200 images. They seem to contain more (albeit initially hidden) detail, and in some sense (can't pin it down) better colour information. They also seem to recover better from underexposure and handle higher exposure more gracefully. I'm enjoying the new lens so much I can't be bothered to do tedious exact like for like comparison tests between them, so perhaps I am imagining some of this. But my overall impression of the 45-175 is very favourable. The decision as to whether to bother trying to process or not is more difficult with the 45-175 because even some “obvious throw-aways” that I tried anyway turned out not too bad, so (given suitable post processing) the images seem to be better than they look at first sight.

    The basic processing of the images is straightforward, using Photoshop CS2. Typically:

    • Check the histogram in Levels and if there is a gap at either end close it up.
    • If the light/colours are still looking particularly flat, increase the Exposure slightly.
    • Apply mild defog/clarity – USM with Amount 7%, Radius 30 pixels, Threshhold zero.
    • Apply a very mild S-curve in Curves, lowering the curve three notches 25% of the way across, and raising it one notch about 65% of the way across.
    • Duplicate layer, set Fill to 9% and ? Mode to Soft Light. Flatten image.
    • Resize to 900 pixels high.
    • Sharpen with Radius 0.3 pixels. The Amount may vary widely, from 20% to 200%.
    This processing is done in RGB mode and as well as bringing up the contrast and micro-contrast it brings up the colours.

    I don't mind a bit of noise in my images, but if it gets too much I start again and use Noiseware with Luminance noise reduction of 34% and Color noise reduction of 0, with Detail Enhancement set to 3 for Sharpness and Contrast. After this I continue as normal. Very occasionally, if I am feeling lazy and don't go back and start again, or if despite initial noise reduction there is still too much noise in the background for my taste, I may apply noise reduction selectively to the background, this time 80% luminance, still 0 color, and 0 for Sharpness and Contrast Detail Enhancement.

    I sometimes raise shadows, for example where the underside of an insect has gone to featureless darkness. When doing this I often turn the Tonal Width down very low, to focus the effects as far as I can on the darkest areas. I may also turn the Color Correction adjustment up a bit from its default value.

    I sometimes cheat compositionally by stretching and/or squashing parts of the background.

    Plus occasional selective burning, dodging, sharpening, cloning etc.
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  15. phdezra

    phdezra Mu-43 Stalker Subscribing Member

    Dec 6, 2011
    New York, NY
    Nick - wow. This is extremely useful and valuable insight. Thank you for taking the time to write this over several posts. :thumbup::thumbup::thumbup: Will digest further.

    Have you tried the Oly 40-150? Or do you use the 45-175 strictly because it is internal focus (less movement = good when photographing insects, not scaring them, etc.)
  16. You are very welcome. :smile:

    No I haven't tried it, and I don't know that I would try any Oly lens, because I'd rather have one with IS, even if IS is for the most part (for my purposes) not much use. Having said that, an Oly 60mm macro, depending on its working distance, might be attractive (but I suspect it's price might not be). I really wish someone would make a longer focal length macro prime for MFT that would play nicely with autoexposure and autofocus.

    The reasons for using the 45-175 are indeed to do with its internal focusing, but not mainly for the reason you suggest (although that does help) but because it makes achromats easier (and quicker) to use, and in the case of the MSN-202, much easier (and quicker) to use. And also (less important, but still useful all the same) because there is no lens drift when shooting downwards.
  17. D@ne

    D@ne Mu-43 Top Veteran

    Feb 23, 2012
    Bumping this thread. Apologies if I'm repeating questions.

    Question to the OP - I assume the two step-up/down rings you have could be combined as one 46-43 step-down? Also, is that a cap on top of the UV filter?

    Next question - how close are you able to focus with this lens? I'm unsure if the macro adapter changes the standard 3' into something more usable. Would this be answered by the "working numbers" you mention above?
  18. Indeed so. I'm only using that strange arrangement because all four achromats were set up for use with the 45-200, which has a 52mm thread. Rather than getting a completely new set of step rings when I got the 45-175 I went for the simpler and cheaper solution of just getting a single 46-52mm step up ring and leaving it on the 45-175 the whole time.

    This cheaper approach was especially appealing because if I sent the lens back because of the "double/soft image at 1/160 sec" problem I would only be left with a single useless step ring rather than four. (It also means that the achromats still fit snugly in their boxes - see next section.) (For the record, I have been fortunate enough not to notice any signs of the double/soft image issue, including series of test shots taken specifically to look for it.)

    There is an added advantage of having the 46-52 step up ring on the camera the whole time. If I mess up the threads with all the changing of achromats that I do, then I would be messing up step ring threads not the thread on the lens. (Conveniently, I also had a 52mm lens cap for the 45-200, which the permanently attached step ring now lets me use on the 45-175.)

    Yes it is. I tend not to leave the achromats on the camera, so the lens cap isn't too important I suppose. When not in use each achromat sits in a box like this, with no bottom cap on the achromat, sitting on top of a foam pad, with the lens cap on top. Under the foam pad there is a bit of packing to make sure the lens fits snugly when the lid is shut, slightly compressing the foam, leaving the lens unable to move. (I am not gentle with the kit bag out in the field.)

    I use little strips of velcro on the outside of the box lids so I can distinguish between the boxes easily - one strip for the 150, two for the 250, three for the 202, and none for the 500D.

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    Yes, those working distance numbers do provide the answer, but it may not be obvious if you are not familiar with how achromats are used.

    A macro lens (as I understand it, I don't have one and have never used one), whether a prime or a zoom, works by letting you get closer than you normally can with a lens of that focal length, which make the subject look bigger. You change the magnification of the subject by moving the lens towards or away from the subject. The maximimum magnification is at the closest distance, known as the Minimum Working Distance, which is measured between the front of the lens and the subject. For example, the Canon 100mm macro lens lets you get the front of the lens to 6 inches from the subject, at which distance the image on the sensor is the same size as the subject (also known as "1:1" magnification).

    With an achromat, you keep the lens at the same distance from the subject and change the magnification by altering the amount of zoom. So, rather than having a "Minimum Working Distance", an achromat has a fixed "Working Distance" between the front of the achromat and the subject. These are the working distances given above, for example 160mm for the Raynox 150 and 32mm for the Raynox MSN-202.

    To work well and give a sharp image, the distance between an achromat and the subject needs to be around the working distance. The more powerful the achromat, the less tolerance there is as to the distance from the subject. With the MSN-202 on the 45-175 for example, I measured the tolerance as about 3mm with the 45-175 at 45mm and nearer to 2mm with the 45-175 at 175mm. This makes the MSN-202 somewhat difficult to use, especially if it is on a lens which changes length as the amount of zoom changes, like the 45-200. It is much, much, much easier to use on the 45-175, which does not change length.
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  19. Correction

    In this post I gave two lists of measurements for working distances etc for four achromats on the 45-200 and the 45-175. I have lost my original notes, but looking at these two lists I am convinced that as originally posted the lists were the wrong way round.

    I have corrected that post.

    My apologies for this mistake.
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