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02-24-2016, 04:41 AM   #1
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Pentax 100mm + macro rings / macro bellows

Hello,
I wanted to ask for some advice
I've been in macro world for 3 or 4 years now with my Pentax 100mm macro lens. This lens gave me everything I wanted, but then I decided to get more magnifying and I bought macro bellows from ebay (those for 30-40 ) and also I got macro rings (yes, the cheapest ones), for a try. And nothing worked. I can't make any picture with macro rings and any picture with macro bellows, while using Pentax 100mm with my Pentax K-3. The view is blurry, focus doesn't work. I tired with my Metz flashlight, nothing helped, used tripod and different source of light.
I wanted to ask, If this is a problem with these cheap macro rings and bellows, that you can't make any picture, or it is with this Pentax macro lens? Maybe I should try with another lens, or to buy good macro bellows / macro rings?

Thank you for your advice.
I am sending few pictures. It doesn't change anything with different camera settings.

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Last edited by Precious; 02-24-2016 at 07:36 AM.
02-24-2016, 05:39 AM   #2
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Surpassing strange, and difficult to give any suggestions without being on-the-spot. But here are some observations.

1) ASSUME AF WILL NOT WORK. AF is generally useless above about 1/3 to 1/4 life size.
2) to experiment, mount the camera on a tripod
3) Manually turn the focus ring on the lens to the closest position
4) hold something in your hand, a stamp or coin, and bring it up to the lens and try to get it into focus
5) REMEMBER: with additional extension, the lens-to-subject distance will be VERY SHORT AND: it is like working with a long telephoto, centering the subject in the FOV is much harder than at lower reproduction ratios.

If the devices you are using have no lenses, if they are only extending the lens farther from the camera body, if you have turned the focus on the lens to the closest position, then your problem is almost certainly finding the point where the lens is focused, both the distance and the centering.

AFTERTHOUGHT!! Remember that the current 100 macro does not have an aperture ring. Therefore, the lens automatically closes to its smallest f-stop unless it is mounted on a device that holds the aperture open. ESSENTIALLY NO AFTER-MARKET BELLOWS (= non-Pentax) HAVE A DIAPHRAGM OPERATING SYSTEM. So on the bellows, you are looking through a lens transmitting at something like f64. SOME TUBES DO, SOME DO NOT HAVE MECHANISM FOR OPERATING THE DIAPHRAGM. If the tubes you bought do not have such a mechanism, then again, you are attempting to see and focus at the equivalent of f64 or less.

FYI: When going to macro, at 1:1 (life size) a lens typically loses two f-stops, so wide open an f2.8 is transmitting brightness at the equivalent of f5.6. If the lens has a minimum aperture of f22, and there is no mechanism for keeping the diaphragm open (as on a bellows that does not have an aperture-operating mechanism), then @ 1:1 the lens is effectively transmitting light at the equivalent of f64. Need I point out that this makes focusing on, or even seeing the subject almost impossible?

---------- Post added 02-24-16 at 08:05 AM ----------

ADVICE: If you want to get above life size, try the Raynox macro lenses, especially the 2.5X (but buy the kit, it's a ridiculous bargain). The Raynox are MUCH, MUCH more convenient and easy to use than bellows or tubes, and the results are far better than with any other close-up filters I have tried, and I have a lot of them. The IQ is competitive with tubes or bellows. I've run experiments, and become a believer and advocate of the Raynox lenses.

Last edited by WPRESTO; 02-24-2016 at 05:59 AM.
02-24-2016, 06:43 AM   #3
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QuoteOriginally posted by WPRESTO Quote
If the devices you are using have no lenses, if they are only extending the lens farther from the camera body, if you have turned the focus on the lens to the closest position, then your problem is almost certainly finding the point where the lens is focused, both the distance and the centering.
This. Your bellows and extension tubes shouldn't stop you from getting something in focus even if they're of the inexpensive variety. They're essentially just spacers between your camera and lens which allow you to focus closer. I'm going to agree with WPRESTO in that I suspect there is some distance at which you're focusing...now you just have to find that point. I'm thinking it might be a lot closer than you suspect. Start by using your bellows at it's shortest extension, then find where it's focusing. Dial in a little bit more extension, then see where things are in focus at that point. Keep going until you get a feel for the range that your bellows gives you with your 100mm lens. Unlike using a regular macro lens, when you're working with a bellows or extension tubes, camera distance from the subject starts playing a much bigger role in things than just the focusing ring on the lens. That's why a lot of people mount their bellows on a focusing rail. As you change extension, it often becomes necessary to change your camera position...and it's a lot easier to move your camera a half inch forward or backward using a focusing rail than try and move your whole tripod.
02-26-2016, 01:57 AM   #4
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Thank you for your advice and explanation about macro bellows and macro rings.

So, I guess it is worth it to buy Raynox?
My Pentax 100mm gets 1:1 magnification, so I think Raynox-250 will be the better choice than Raynox-150?


Last edited by Precious; 02-26-2016 at 02:46 AM.
02-26-2016, 04:44 AM   #5
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QuoteOriginally posted by Precious Quote
Thank you for your advice and explanation about macro bellows and macro rings.

So, I guess it is worth it to buy Raynox?
My Pentax 100mm gets 1:1 magnification, so I think Raynox-250 will be the better choice than Raynox-150?
I would advise getting the kit that includes both. It's about $103 at B&H. Have you checked to see if the diaphragm is open or closed when you mount the 100mm macro with one of the extension tubes onto a camera? The more I think about it, the more I'm inclined to think that the tubes do not have a diaphragm operating mechanism and you're attempting to frame and focus with a lens that is stopped down to the equivalent of f64 or less.
02-26-2016, 06:13 AM - 1 Like   #6
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QuoteOriginally posted by WPRESTO Quote
The more I think about it, the more I'm inclined to think that the tubes do not have a diaphragm operating mechanism and you're attempting to frame and focus with a lens that is stopped down to the equivalent of f64 or less.
If the lens is the D FA 100mm f2.8 WR, then that is most assuredly the problem. You need an aperture ring on the lens to use bellows or extension tubes.
02-26-2016, 06:52 AM   #7
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What sort of magnification are you looking for extreme macro? I get about 8.4× using the Pentax Auto Bellows A and a 25mm enlarging lens (for half-frame 35mm negatives). A 25mm prime reversed coupled on a 200mm lens will give you ~4×.

02-26-2016, 07:22 AM   #8
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QuoteOriginally posted by Not a Number Quote
What sort of magnification are you looking for extreme macro? I get about 8.4× using the Pentax Auto Bellows A and a 25mm enlarging lens (for half-frame 35mm negatives). A 25mm prime reversed coupled on a 200mm lens will give you ~4×.
The Raynox are more-or-less the equivalent of using a shot FL lens or enlarging lens reversed on a moderate telephoto, but with an extremely quick/convenient clip-on mount (fits filter threads 52-62mm). And again I have run tests, and the IQ delivered by the Raynox units is excellent, definitely competitive with other mechanisms in the life-size to about 3X life-size range.

AND, a 25mm prime reversed on 100m would give 4X; on 200mm it would be 8X. I'm sure that's a typing error on your part.
02-26-2016, 08:20 AM   #9
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QuoteOriginally posted by audiobomber Quote
If the lens is the D FA 100mm f2.8 WR, then that is most assuredly the problem. You need an aperture ring on the lens to use bellows or extension tubes.
Yes, its the D FA 100mm f2.8 WR. I've never imagined about aperture ring before.. Its silly to ask, but what kind of aperture ring should be used?




---------- Post added 02-26-16 at 08:25 AM ----------

QuoteOriginally posted by WPRESTO Quote
I would advise getting the kit that includes both. It's about $103 at B&H. Have you checked to see if the diaphragm is open or closed when you mount the 100mm macro with one of the extension tubes onto a camera? The more I think about it, the more I'm inclined to think that the tubes do not have a diaphragm operating mechanism and you're attempting to frame and focus with a lens that is stopped down to the equivalent of f64 or less.
I checked today and the diaphragm is closed when I mount extension tube or bellows.. So there is the problem
Finally. Thanks, now I now where the problem was.

Last edited by Precious; 02-26-2016 at 08:25 AM.
02-26-2016, 11:00 AM   #10
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QuoteOriginally posted by Precious Quote
Yes, its the D FA 100mm f2.8 WR. I've never imagined about aperture ring before.. Its silly to ask, but what kind of aperture ring should be used?
The aperture ring is part of the lens. The older D FA 100mm macro had one, the WR version doesn't:



I haven't seen K-mount bellows or tubes with an aperture ring, but maybe there is such a thing. I've never looked because I have the older D FA 100mm.

A Raynox is a possibility for you. My favourite means for increasing magnification is a good quality teleconverter.
02-26-2016, 11:52 AM   #11
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Pentax-made bellows in K-mount have a diaphragm operating mechanism where the lens was mounted. Basically it's a spring-operated lever that keeps the diaphragm open until pulled back using a mechanical cable release threaded into the front standard of the bellows. Thus, there was no communication between camera lens. Pentax provided a "double" cable release = two flexible cables operated by a single thumb-press plunger. One cable went to the front standard of the bellows to operate the lens diaphragm, the other went to the standard threaded cable release socket on the camera. There was an adjustment mechanism to insure that triggering the shutter required slightly more travel by the plunger than closing the diaphragm, so the latter is always fully closed before the shutter is triggered.
02-26-2016, 01:30 PM - 2 Likes   #12
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Below are four images from a long series of experiments on various close-up macro/micro systems. No PP except cropping as indicated. f8 for all images. Camera = K5, best JPEG
From uppermost down:

1) 200mm f4 SMCA Pentax with reverse mounted 100mm f4 Pentax bellows lens, uncropped
2) CROP from same image file as preceding.
3) 70mm f2.4 DA with 2.5X Raynox (using a stepping ring to mount), uncropped
4) CROP from same image file as preceding.

Close examination of the surface texture and greenish corrosion on the crops gives an indication of the IQ, within the limits of the file size permitted on PF (these were saved for 1024 pixels maximum width)
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02-27-2016, 11:04 AM   #13
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QuoteOriginally posted by audiobomber Quote
The aperture ring is part of the lens. The older D FA 100mm macro had one, the WR version doesn't:



I haven't seen K-mount bellows or tubes with an aperture ring, but maybe there is such a thing. I've never looked because I have the older D FA 100mm.

A Raynox is a possibility for you. My favourite means for increasing magnification is a good quality teleconverter.
So, I guess there is no way to use bellows or macro rings normally with this lens. Thanks anyway
02-27-2016, 12:19 PM   #14
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QuoteOriginally posted by Precious Quote
So, I guess there is no way to use bellows or macro rings normally with this lens. Thanks anyway
Only using one of the discontinued K-mount Pentax bellows. As noted above, these have a diaphragm operating mechanism in the front standard that is operated using a mechanical cable release. Press the cable release to close the diaphragm.

Another point against tubes & bellows when trying to get above life size. The amount of extension needed starts to get really, really larg, and therefore the whole rig becomes very clumsy, even on a tripod (which is absolutely necessary). Reverse mounting a lens, or stacking a reversed short SFL lens on a long SFL lens, or using the Raynox achromatic filters provides a far more compact, easy-to-handle rig.
02-27-2016, 01:02 PM - 1 Like   #15
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Additional images from my tests of macro options.

1) a 200mm SMCA mounted on a Pentax bellows that has a diaphragm operating mechanism (notice the mechanical cable release threaded into the front standard). Fully extended as shown, this rig provides approximately the same magnification as the 70mm f2.4 with a 2.5X Raynox attached;
2) penny photographed with the preceding rig - compare to the image posted earlier of a penny taken with a 70mm f2.4 + Raynox 2.5X;
3) crop from preceding image file; the IQ with this rig is very good.
4) on left a set of K-mount Kenko extension tubes that have diaphragm operating linkage and aperture information transfer contacts; on right a Kenko Uniplus Tube, 25mm length, that has aperture information contacts, diaphragm operating linkage, and AF connection. SFAIK Kenko no longer offer either of these in K-mount.
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Last edited by WPRESTO; 02-27-2016 at 01:27 PM.
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