[BrianR]

I worked out the magnification of the DFA 100mm (non-WR version) coupled with the Raynox DCR-250 using the practical 'ruler test' and thought others might be interested.

Short Version

As you move from infinity focus down to minimum focus, the magnification of this combo ranges from ~0.8X to ~2X and the working distance drops from 12cm down to 5.5cm.


Long Version

There is a great calculator here, but it gets significantly off for the DFA100mm as the focal length changes throughout the focusing range (I figure it's approx. 75mm at min. distance) and the front element is deeply recessed. Test setup was simple, I lined the focus mark up with the different magnification markings on the focusing scale, moved until my subject (a ruler) was in focus using liveview, then measured things. All measurements are approximate. The Raynox was attached using a single 49-43mm step down ring.

Barrel Marking 1/x	FoV in mm	Magnification	Working Distance	Focusing Distance
Infinity	30	0.79X	120	265
25	28	0.85X	115	261
10	26	0.91X	107	254
5	23	1.03X	95	247
4	22	1.08X	92	246
3	20	1.19X	84	243
2.5	18.5	1.28X	80	243
2	17	1.39X	74	240
1.5	15	1.57X	67	242
1.2	13	1.82X	62	243
1	12	1.98X	55	248

Column Notes:

Barrel Marking 1/x - Magnification marked on the lens scale. "x=25" corresponds to 1/25= 0.04X magnification, "x=2" corresponds to 1/2=0.5X magnification or half life size, etc. I lined the focus mark up with the centre of the text on the scale. "x=Infinity" isn't marked on the scale, but this entry corresponds to Infinity focus.

FoV in mm - Ruler was in landscape orientation, that is, this measurement is the long side of the frame. Camera was APS-C k5iis.

Magnification - The long side of the k5iis sensor is 23.7mm, this column is 23.7/FoV.

Working Distance - Measurement from the front of the ruler to the front of the Raynox adapter in millimeters. This is how far the front of the camera is to your subject.

Focusing Distance - Measurement from the subject to the tripod socket (roughly where the sensor is) in millimeters. Note the trend as it goes down, then back up again as the focal length of the lens changes with the different focusing distances. Measurements are approximate, but you most definitely have to move the camera back out to maintain focus as you move from the "1/2" mark down to "1/1".


End Notes:

I think we'd get more magnification if the front element wasn't so deeply recessed, but it is what it is. It's kinda handy to be able to continuously range from ~0.8x to ~2x magnification with this setup (or just under life size to double life size), and also pretty convenient in practical use that the focusing distance hardly changes. The quality of this raynox is impressive, at some point I'll do a comparison at around 1X magnification using the adapter vs not using the adapter to see if I can tell which is which (I suspect it will be close).

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Last edited by BrianR; 08-04-2016 at 03:35 PM.

[UncleVanya]

I have done some experimenting with TC's on mine but despite owning the raynox 150 and 250 I hadn't tried this. Interesting results.

[WPRESTO]

Generally speaking close-up filters work best when as close to the front element as possible. I'm not sure whether the 100 + Raynox will show either at its best.

[Doundounba]

I've been super happy with this combo! (I have the non-WR version of the D-FA 100mm.) I'm attaching a couple of samples below, or you can also have a look over here. I've used the Raynox DCR-250 with a Tamron 90mm Macro, with a Vivitar Series 1 105mm Macro, and with various Adaptall lenses, and I think the combo with the Pentax is just as strong as any of the others. And the lightness of the Pentax lens is a big plus for me. Also, as the OP states, the range (1:1.3 to 2:1) is really useful.

BTW, I've found a side-benefit to shooting with the Raynox for around lifesize (or 1:1) shots. Because the lens is much less extended than it would be for a 1:1 shot without the Raynox, and the working distance is about the same, my diffuser winds up much closer to the critter than if I was using just the D-FA by itself. What this translates to is softer light! (The downside is, since the diffuser gets really close, your effective working distance becomes the distance between the critter and the diffuser rather than the distance between the critter and the lens, and some critters will not be comfortable with the diffuser so close, and just leave.)

BTW, BrianR: I believe that the K-5 IIs sensor is actually 23.7mm rather than 23.5mm (which is the size of the K-3 sensor).

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Last edited by Doundounba; 08-04-2016 at 07:21 PM.

[BrianR]

Generally speaking close-up filters work best when as close to the front element as possible. I'm not sure whether the 100 + Raynox will show either at its best.

I've been wondering how much differerence sawing off the front of the barrel would make but I don't think I could bring myself to chopping up such a fine lens. Even with the gap, it's a pretty cracking combo.

BTW, BrianR: I believe that the K-5 IIs sensor is actually 23.7mm rather than 23.5mm (which is the size of the K-3 sensor).

Sigh, serves me right for going from memory and not double checking. I've updated the OP. Thanks!

Nice examples, and I hear you about the lightness. It's worth a side-by-side comparison with 100mm macros from other brands to fully appreciate its sveltness.

[BrianR]

I repeated the above for the DA*300mm and DCR-250. Everything as above except I did the measurements at the focusing distances marked on the barrel (in metres). All measurements are very approximate, especially the FoV in mm, but the general trend should be accurate.

The take away - the DCR 250 gives more magnification and significantly more working distance with the DA*300mm than the DFA100mm (of course), but much less flexible in the magnification as the focus barrel turns and definitely much harder to handhold (increased mag. and greatly increased weight).

Quick tests looked positive, but no time at the moment to do a fair evaluation. The working distance is certainly promising.

Focus Distance on Barrel	FoV in mm	Magnification	Working Distance	Focusing Distance
Infinity	10	2.37X	118	374
10	10	2.37X	115	371
5	10	2.37X	113	369
3	9.8	2.42X	111	367
2.5	9.7	2.44X	110	366
2	9.5	2.49X	108	364
1.7	9.4	2.52X	107	363
1.5	9.3	2.55X	106	362
1.4	9.2	2.58X	105	361

[BrianR]

Thought I'd add the DFA50mm + DCR250, as expected the closeup filter's effect is much reduced on a shorter focal length lens. Working distance also becomes peanuts. As before, measurements are approximate, but the magnifications should be pretty good (subject to my ability to accurately line up the vague barrel markings). Units in mm. No test photos yet, I would probably need to be in a pinch to actually use this combo.

Barrel Marking 1/x	FoV in mm	Magnification	Working Distance	Focusing Distance
Infinity	56	0.42X	111	234
25	52	0.46X	106	230
10	46	0.52X	91	218
5	39	0.61X	72	207
4	37	0.64X	67	202
3	32	0.74X	56	195
2	27	0.88X	43	188
1.5	23	1.03X	35	186
1.2	20	1.19X	27	186
1	18	1.32X	25	189

[UncleVanya]

Thought I'd add the DFA50mm + DCR250, as expected the closeup filter's effect is much reduced on a shorter focal length lens. Working distance also becomes peanuts. As before, measurements are approximate, but the magnifications should be pretty good (subject to my ability to accurately line up the vague barrel markings). Units in mm. No test photos yet, I would probably need to be in a pinch to actually use this combo.

Barrel Marking 1/x	FoV in mm	Magnification	Working Distance	Focusing Distance
Infinity	56	0.42X	111	234
25	52	0.46X	106	230
10	46	0.52X	91	218
5	39	0.61X	72	207
4	37	0.64X	67	202
3	32	0.74X	56	195
2	27	0.88X	43	188
1.5	23	1.03X	35	186
1.2	20	1.19X	27	186
1	18	1.32X	25	189

You might also want to work out what the DCR150 and/or the combo of both does on the DFA 100. Most of my use on shorter focal length lenses has been on non-macro lenses like the DA 70 and the FA 77. My longer focal length use has been on the DA* 200 and the FA* 300 as well as the DA* 60-250. You could also (if you have it) toss the 1.4x TC onto the DFA 100 and see what that adds when using the Raynox.

[BrianR]

You might also want to work out what the DCR150 and/or the combo of both does on the DFA 100. Most of my use on shorter focal length lenses has been on non-macro lenses like the DA 70 and the FA 77. My longer focal length use has been on the DA* 200 and the FA* 300 as well as the DA* 60-250. You could also (if you have it) toss the 1.4x TC onto the DFA 100 and see what that adds when using the Raynox.

Alas, I don't have the DCR150.

I do have the Tamron 1.4x teleconverter. When added to the dfa100mm&DCR250, it multiplies the magnification by 1.4 (near enough given measurement error, though I didn't make great efforts for accuracy and only checked the endpoints at infinity and minimum focus) with no appreciable change in working distance. In other words, when you have the raynox+lens+camera focused on the subject, the camera moves back to make room for the teleconverter as opposed to the lens having to move forward. I'd never looked at it that closely in a situation where every mm counts, so that's nice.

[Perfessor5646]

Gosh, it’s my lucky week finding this thread. I had a DFA 100 WR and 1.4X TC already and thanks to the work posted here by BrianR and others and doundounba’s samples and flickr page, my Raynox DCR 250 and adapter arrived today. Already played with it a bit on my front porch. There is a butterfly exhibit at the local zoo. Let me play with lighting and exposure settings and I’ll be ready to go.

[Perfessor5646]

Illuminated by Pentax 360 on the hot shoe diffused with Mag Mod Mag Sphere.

Yesterday I found this girl seeking shelter from the rain under a leaf on a Front Porch Safari. It was a challenge but I like this one.

[Doundounba]

Since this thread has been revived, I just want to say that I've upgraded from the non-WR to the WR version of the D-FA 100mm. Better build quality and WR are much appreciated, and the combo with the DCR-250 remains what I shoot about 90% of the time. Right now, I go out with that combo on the K-3, and in the bag I bring along the HD DA 1.4X, the DA 35mm Macro, and a Pentax-M 135mm F/3.5 with Raynox MSN-202 pre-installed.

Here are some favorites from last season, with just the D-FA 100mm WR plus Raynox DCR-250 (and flash, of course). BTW, 2nd and 3rd are focus stacks.