[UncleVanya]

The DCR-150 is +4.8 and the DCR-250 is +8 diopters. Using that and the lens info available at Pentax Forums and this site at Cambridge in Color (Scroll down past extension tubes) you can calculate this yourself for any number of combinations.

Macro Extension Tubes & Close-up Lenses

Extreme Macro site may give better more accurate data:
Using Raynox Adapters For Extreme Macro

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Last edited by UncleVanya; 07-05-2018 at 09:04 AM.

[UncleVanya]

Raynox 250 + the first version of the 18-55mm kit lens:

At 55mm & minimum focus distance: working distance ~ 6cm, magnification ~0.75X

At 55mm & infinity focus: working distance ~ 12cm, magnification ~0.4X

It vignettes terribly at 18mm with the Raynox. I can't speak for quality when paired with the kit lens, I mostly use the Raynox 250 with my macro for more magnification and the results are pretty great.

The native magnification factor of the 18-55 AL (original) is 0.34x at 55mm (I assume at 55mm) and plugging that into the calculator with an 8 diopter filter I get 0.93x magnification.

I think you plugged in the DCR-150 by mistake? The two sites I checked gave similar results. The working distance appears close to the same however.

Alternatively there is an error somewhere in both sites I used.

[BrianR]

The native magnification factor of the 18-55 AL (original) is 0.34x at 55mm (I assume at 55mm) and plugging that into the calculator with an 8 diopter filter I get 0.93x magnification.

I think you plugged in the DCR-150 by mistake? The two sites I checked gave similar results. The working distance appears close to the same however.

Alternatively there is an error somewhere in both sites I used.

I did it the old fashioned way, by aiming at a ruler with the combo on the camera. At minimum focus distance, 55mm, with the Raynox 250 (the only one I own), my aps-c camera (~24mm wide sensor) has a field of view 32mm wide.

The formulas will give approximations based on idealized, simple lenses and positioning of the close up diopter. I expect this accounts for the difference, but I'm always open to the possibility that I completely screwed up. I can't seem to find any posts that confirm the magnification of this combo using a practical test.

[UncleVanya]

I did it the old fashioned way, by aiming at a ruler with the combo on the camera. At minimum focus distance, 55mm, with the Raynox 250 (the only one I own), my aps-c camera (~24mm wide sensor) has a field of view 32mm wide.

The formulas will give approximations based on idealized, simple lenses and positioning of the close up diopter. I expect this accounts for the difference, but I'm always open to the possibility that I completely screwed up. I can't seem to find any posts that confirm the magnification of this combo using a practical test.

I no longer have an 18-55 to test with so I can't even double check it. But I will try to check the calculator against some other combinations. The 0.34x is a very high value for a non-macro lens but that seems consistent for most models so I suspect it is accurate.

[UncleVanya]

Focus breathing may play a role. The 18-55 may not be 55mm at these distances before adding the Raynox. If the focal length slightly shrinks that would explain the loss of magnification.

[WPRESTO]

What do you think the focal distance will be using the Raynox 250 on top of the 18-55mm kit lens? What is the furthest distance one can focus at for good quality shots?

Note that BrianR has given some precise information.

These are the rules for Raynox:
1) with the 150 (+1.5X) with the lens set to infinity, the distance from the front element of the lens to the subject will be about 8 inches regardless of the focal length of the lens.
2) with the 250 (+2.5X) with the lens set to infinity, the distance from the front element of the lens to the subject will be about 4 inches regardless of the focal length of the lens.
3) because the front element to subject distance is the same with the lens @ infinity when a Raynox (or any close-up filter) is attached, longer focal length lenses or longer FL settings on a zoom lens will yield higher magnification.

4) how much closer you can focus by turning the focus ring on your lens depends upon the focal length of the lens and how close the lens will focus without the Raynox attached, Again, you cannot predict in advance.

5) the performance of the Raynox on a zoom lens cannot be predicted in advance. With some zooms and some FL settings, there may be severe vignetting yet the center will have excellent IQ (see example I posted with a Raynox on a SIgma 17~70mm). With other zooms, there may be no vignetting over the entire FL range. In general, vignetting is far more likely at short FL settings with a zoom, and almost always, a good quality single focal length lens will yield better IQ with a Raynox than a zoom.

[BrianR]

I no longer have an 18-55 to test with so I can't even double check it. But I will try to check the calculator against some other combinations. The 0.34x is a very high value for a non-macro lens but that seems consistent for most models so I suspect it is accurate.

I had to dig mine out of a drawer. The 0.34x max magnification for the bare 18-55mm is accurate I believe. I was fairly quick and approximate. If you want some other combos to check, I took more care in the practical tests I did with the dfa100mm and the DA300mm

[stevebrot]

So the Pentax/Cosina/Vivitar et al.... are the same lens. Mine did not have the matched Diopter but at 2:1 it works fine. Mine cost about $75.00 at a local camera store.

The matched converter is required for the lens to attain 1:1. 1:2 is probably not adequate to show makers-mark or condition of jewelry. The Pentax version (FA 100/3.5 Macro) of this particular macro lens (made by Cosina and available in multiple brands) is a bit of an enigma within the Pentax line, even for the time. Optical quality is good, but the build is not up the same standard as other FA-series nor does it resemble any other FA-series lens.


Steve

[stevebrot]

If jewels don;t sparkle and don;t have deep color why get them? sorry they look bland.

Don't taunt the wheatman! The image is a nice illustration of what is easily accomplished with a dedicated macro.


Steve

[stevebrot]

A note about working distance. It is not the same as minimum focus distance. The latter is usually much greater when working in the macro range.


Steve

[UncleVanya]

Note that BrianR has given some precise information.

These are the rules for Raynox:
1) with the 150 (+1.5X) with the lens set to infinity, the distance from the front element of the lens to the subject will be about 8 inches regardless of the focal length of the lens.
2) with the 250 (+2.5X) with the lens set to infinity, the distance from the front element of the lens to the subject will be about 4 inches regardless of the focal length of the lens.
3) because the front element to subject distance is the same with the lens @ infinity when a Raynox (or any close-up filter) is attached, longer focal length lenses or longer FL settings on a zoom lens will yield higher magnification.

4) how much closer you can focus by turning the focus ring on your lens depends upon the focal length of the lens and how close the lens will focus without the Raynox attached, Again, you cannot predict in advance.

5) the performance of the Raynox on a zoom lens cannot be predicted in advance. With some zooms and some FL settings, there may be severe vignetting yet the center will have excellent IQ (see example I posted with a Raynox on a SIgma 17~70mm). With other zooms, there may be no vignetting over the entire FL range. In general, vignetting is far more likely at short FL settings with a zoom, and almost always, a good quality single focal length lens will yield better IQ with a Raynox than a zoom.

I am getting much closer than 8 inches using the DCR-150 on the 18-50 and the 18-135 both at max zoom. However item 5 seems to say this could be related. 18-135 vignettes until close to 100mm BTW.

With the 18-50 (just verified right now) I get under 3" to the subject from the front element.

[GoldMountain]

There is a Vivitar Series 1 105 2.5 PKA for sale in the marketplace. Same lens as the Lester Dine.

Kiron / Lester A. Dine 105mm f2.8 Macro Lens Reviews - Miscellaneous Lenses - Pentax Lens Review Database

Are the Pentax equipment prices generally better in this forum marketplace or on eBay?

[WPRESTO]

IWith the 18-50 (just verified right now) I get under 3" to the subject from the front element.

With the lens FOCUSED AT INFINITY? That is the point. The Raynox 150 should bring any lens, any focal length into focus at eight inches WHEN THAT LENS IS FOCUSED TO INFINITY. How much closer than that you can focus depends, as stated, on both the focal length of the lens and how close the lens can focus without the Raynox attached.

This is exactly the same way any and all close-up filters work, For example: a +4 close up lens will cause any lens, any focal length to have a front-of-lens-to subject, in-focus distance of approximately 250mm WHEN THE LENS IS FOCUSED AT INFINITY.

The ancient rule: with a lens focused at infinity, when a close-up filter is attached, the lens front to subject focus distance becomes 1000mm divided by the diopter value of the close-up filter, regardless of the focal length of the lens.

[UncleVanya]

With the lens FOCUSED AT INFINITY? That is the point. The Raynox 150 should bring any lens, any focal length into focus at eight inches WHEN THAT LENS IS FOCUSED TO INFINITY. How much closer than that you can focus depends, as stated, on both the focal length of the lens and how close the lens can focus without the Raynox attached.

No, I misread you. At Infinity I am close to 8" with the 18-50.
Thanks for helping me muddle through this.

[WPRESTO]

No, I misread you. At Infinity I am close to 8" with the 18-50.
Thanks for helping me muddle through this.

No problem. It's taken me 50+ years to understand this, almost.