[Nick Siebers]

Yeah, extension tubes are an easy and cheap way to great macro, provided you have a lens that will work on them (has an aperture ring). And I had a Pentax-M 50mm f/4 macro that gave incredible image quality, that sold on the bay for less than $100. Only 1:2, but I think you could just about isolate one grape. Certainly with a little judicous cropping.

[audiobomber]

I am a Raynox DCR 150 user and proponent.

It is a handy adjunct to your kit and will do high quality images if you don'tcare about the edges.

IQ is good within a circlular area in the frame's center. This is most often not a problem as items photographed will be in the frame center, but it will fail on an image that requires edge-to-edge sharpness. It is not a complete replacement for a good macro lens.

The biggest difference I find between a macro lens and a Raynox is DOF. As your calculations showed, you only get about half a slice of depth compared to similar magnification by a true macro lens. I suspect that's what you're seeing with the edges. I do find a slight loss in resolution (Raynox vs dedicated macro lens), but it's only visible with extreme pixel peeping.

[newarts]

So far as I know, for a particular camera & display, Depth of Field depends only on f-number and magnification. It doesn't matter how one gets that magnification; ie macro lens, regular lens plus close-up lens, regular lens plus teleconverter, whatever.

Dave

[Just1MoreDave]

The biggest difference I find between a macro lens and a Raynox is DOF. As your calculations showed, you only get about half a slice of depth compared to similar magnification by a true macro lens. I suspect that's what you're seeing with the edges. I do find a slight loss in resolution (Raynox vs dedicated macro lens), but it's only visible with extreme pixel peeping.

That Raynox is really irritating. I have four dedicated macro lenses that ought to out-resolve it and give me spectacular results. I have extension tubes and reversing rings and flash brackets. I'm starting to think that I need talent. Where can I get that, cheap?

[GerryL]

I'm starting to think that I need talent. Where can I get that, cheap?

Practice??

Hey Dave, I know this is off-topic but I see you have a Vivitar mirror lens.
Why not write a review of it on the lens review database.
I'm curious about that lens and how it performs.
Maybe you have practiced more on this (Vivitar 500mm) to provide better results??
Do you have any links to photos taken with it?

[audiobomber]

So far as I know, for a particular camera & display, Depth of Field depends only on f-number and magnification. It doesn't matter how one gets that magnification; ie macro lens, regular lens plus close-up lens, regular lens plus teleconverter, whatever.

Dave

I don't know the physics of it Dave, but I know what I see. I just did some tests at F11 using the DFA 100 macro vs Raynox 150 + DA 55-300 (set at 210mm and infinity focus for 1:1 macro). The Raynox shows far less DOF. I can post some test shots later. Even better, try the test yourself.

[audiobomber]

I'm starting to think that I need talent. Where can I get that, cheap?

Sorry Dave, you're asking the wrong guy.

You should get a Raynox for the fun factor. The DOF issue discussed above makes it harder to handle than a dedicated macro lens, but it has its advantages;
- it's easy to get beyond 1:1 and maintain auto operation
- pop-on pop-off convenience (or use an adapter and mount it like a filter)
- more compact than any macro lens and mounts on virtually any lens, so no reason to leave it behind.
- inexpensive (about $50 at Adorama or B&H)
- good working distances (subject distance about double for a Raynox 150 compared to a D FA 100mm).

I thought to try a 49mm rubber hood with a Raynox today and it works beautifully. That should address one of the weaknesses of the Raynox system (no hood therefore subject to flare). Looks cool too.

[Marc Sabatella]

Hey Dave, I know this is off-topic but I see you have a Vivitar mirror lens.
Why not write a review of it on the lens review database.
I'm curious about that lens and how it performs.
Maybe you have practiced more on this (Vivitar 500mm) to provide better results??
Do you have any links to photos taken with it?

BTW, as you may or may not know, I have this same lens. I've only had it for a month or so and wish to use it a bit more before actually posting a review, but I can tell you a few things about it:

- Mirror lenses are tough creatures on a number of levels; some won't like *any* mirror lens just because of the donut bokeh, the small fixed aperture, the low contrast, and the difficulty handholding and shallow DOF that come from *any* lens with that long a focal length. but with practice and appropriate PP, mirror lenses can yield very good results.

- The Vivitar (aka Samyang, Phoenix, Opteka, and Quantaray) is not one of the better mirror lenses out there - sharpness and contrast both lower than some, plus it loses enough of the light let in by by its f/8 aperture that its effective aperture is more like f/11 or so in terms of the kind of exposure you can expect. All mirror lenses do this to some extent, but this one seems worse than average.

- For whatever reason, the donut bokeh seems less noticeable on this than other mirror lenses.

- It is surprisingly well-made for the price, and significantly smaller and lighter than most others. Plus it's easily available for little money, something one cannot say for most of the lenses that might outperform it.

- When you've got enough light to use it, and you clean up the contrast and sharpness in PP, it can produce "decent" images. Probably a little better than simply cropping the results from a 200 or 300 if you don't mind having much less light to work with and shallower DOF, and probably better in all respects than trying to use "most" shorter lenses with "most" TC's (combinations which won't do any any better than the 500 mirror in terms of aperture or DOF).

Since this is off-topic, I'll post just links to some images:

http://farm3.static.flickr.com/2510/3794923667_6a743005b6_b.jpg

http://farm3.static.flickr.com/2552/3788064180_88e9fd0316_b.jpg

http://farm4.static.flickr.com/3541/3801499799_d0c339d77d_b.jpg

http://farm4.static.flickr.com/3479/3705987714_4e8eeb5518_b.jpg

[Marc Sabatella]

I do find a slight loss in resolution (Raynox vs dedicated macro lens), but it's only visible with extreme pixel peeping.

Also, the resolution of the Raynox is limited by the resolution of the lens you use it with. A lens that it isn't as sharp as a given dedicated macro lens won't magically become sharper when you stick a Raynox in front. But if your "host" lens is sharp enough, you really won't notice any loss in sharpness from the Raynox.

[audiobomber]

I don't know the physics of it Dave, but I know what I see. I just did some tests at F11 using the DFA 100 macro vs Raynox 150 + DA 55-300 (set at 210mm and infinity focus for 1:1 macro). The Raynox shows far less DOF. I can post some test shots later. Even better, try the test yourself.

D FA 100mm Macro, F11, minimum focus distance


DA 55-300mm @ 210mm, F11, infinity focus

[Pentaxor]

D FA 100mm Macro, F11, minimum focus distance


DA 55-300mm @ 210mm, F11, infinity focus

inorder to get a decent or deeper DOF, you need to decrease the FL at 150mm. 100mm would be the magic number for the Raynox + 55-300mm. it is apparent that a dedicated macro have an advantage of having a deeper DOF at a fixed focal length at a certain focusing distance. however, a high grade diopter lens could atleast match the same depth of the DOF at the same focal length (100mm) by adjusting the focusing distance and moving to and fro from the subject. an increase in the focal length would mean a much thinner DOF, so adjusting the aperture and focusing distance and compensationg the distance between you and the subject would be necessary. but the lens can do so much and has it's limits as well. at 300mm, the DOF is just so thin that it becomes unusable.

I did however tried putting a diopter lens on a macro and it appears that that combination is much better as compared to using a telephoto zoom. the image is still better in terms of DOF. however, I'm just wondering how would a 200mm or 300mm prime telephoto lens + diopter lens would look like. but considering the image quality of a prime lens, the results could be better as compared to that of a zoom telephoto. this of course basing from the 100mm macro result, with the exception that it has a much higher magnifaction already (1:1 + +3 diopter lens). if I used a premium grade 135mm prime lens + diopter, I think the results would be magnificent.

[audiobomber]

inorder to get a decent or deeper DOF, you need to decrease the FL at 150mm. 100mm would be the magic number for the Raynox + 55-300mm. it is apparent that a dedicated macro have an advantage of having a deeper DOF at a fixed focal length at a certain focusing distance. however, a high grade diopter lens could atleast match the same depth of the DOF at the same focal length (100mm) by adjusting the focusing distance and moving to and fro from the subject. an increase in the focal length would mean a much thinner DOF, so adjusting the aperture and focusing distance and compensationg the distance between you and the subject would be necessary. but the lens can do so much and has it's limits as well. at 300mm, the DOF is just so thin that it becomes unusable.

Are you maybe talking about the Raynox 250? It has a focal length of 109mm, which would give almost 1:1 macro at 100mm. For the photos above I used a FL of 210mm, which is the stated focal length of the DCR-150 and therefore gave me 1:1 macro. If I had set the 55-300 for 100mm, I would get more DOF, but I would not get 1:1 macro. If I try to move in too close, I lose focus.

The DCR-150 is quite useable on the 55-300mm at 300mm, but you need an extremely small aperture for a useable DOF. The result is about 1.4:1, pretty serious magnification. At 300mm I normally use an aperture of F32 and a flash.

I'll respond to the rest of your post after I try another test.

[Marc Sabatella]

My read of the situation is that the actual size of the zone of acceptable focus as defined by a DOF formula would be the same (or very close to it) in these two shots, but because the Raynox was shot at a much higher FL, the OOF areas appear *more* OOF than they are in the 100mm shot. Thus, area that were't actually in critically sharp focus with the 100 are close enough to being in focus that you can still perceive them as pretty good, but those same areas are less close close to being in focus on with the Raynox.

The point being, we are seeing a different in the appearance of DOF that depends on FL, not on whether you are using a Raynox or not. My assumption is that a 200mm macro lens at the same distance as the 55-300 @ 200 with Raynox would show something much closer to the same DOF.

In fact, you could test this to some extent by setting the 55-300 to *minimum* instead of *maximum* focus, which would give you the same magnification at a lower FL, and seeing how that affected the appearance of the DOF. I'd hypothesize you'd get 1:1 magnification around 135mm (well you would with the M135/3.5, anyhow, and that could be enough to show the effect. Not sure how the minimum focus distance of the 55-300, combined with the effect of diminish focual length at short focus distances, would affect that.

[audiobomber]

My read of the situation is that the actual size of the zone of acceptable focus as defined by a DOF formula would be the same (or very close to it) in these two shots, but because the Raynox was shot at a much higher FL, the OOF areas appear *more* OOF than they are in the 100mm shot.

That sounds kind of semantic. The fact is, the useable area of the macro lens is larger.

The point being, we are seeing a different in the appearance of DOF that depends on FL, not on whether you are using a Raynox or not. My assumption is that a 200mm macro lens at the same distance as the 55-300 @ 200 with Raynox would show something much closer to the same DOF.

I suspect you're right. And a DA 35mm Limited would show more DOF than the DFA 100 at 1:1 macro.

In fact, you could test this to some extent by setting the 55-300 to *minimum* instead of *maximum* focus, which would give you the same magnification at a lower FL, and seeing how that affected the appearance of the DOF.

I did a quick and dirty test at minimum focus. I got to 1:1 at around 150mm and DOF was better. Interesting, I'll have to keep that in mind.

I'd hypothesize you'd get 1:1 magnification around 135mm (well you would with the M135/3.5, anyhow, and that could be enough to show the effect. Not sure how the minimum focus distance of the 55-300, combined with the effect of diminish focual length at short focus distances, would affect that.

The minimum focus distance of the 55-300 is about a meter? I believe this limits how much magnification is achievable with a diopter at minimum focus.

[Marc Sabatella]

That sounds kind of semantic. The fact is, the useable area of the macro lens is larger.

Of course, but I needed to establish that in order to support my hypothesis as to *why* you were seeing a difference: that is, it is not Raynox versus macro, but 210mm versus 100mm. And then also circumvent the inevitable complaint that such-and-such a DOF calculator says the DOF should be the same regardless of FL :-)

The minimum focus distance of the 55-300 is about a meter? I believe this limits how much magnification is achievable with a diopter at minimum focus.

I just looked it up - 1.4m according to Dimitrov's site. That's about the same as the M135/3.5 (1.5m). So *if* the focal lengths match at focus distances that short, that might suggest the 55-300 would give you 1:1 around 135mm at minimum, just like the M135/3.5 does. Since it is known that with most lenses their focal lengths change as you focus closer, and that this is effect is more pronounced on zooms than primes, it doesn't surprise me you needed to dial it to 150mm to get the same magnification as the M135/3.5.

Would be interesting to see how the Raynox 250 on an ordinary 100mm lens compares with the 100mm macro! Seems quite plausible we'd get a pretty good match in terms of focus distance, magnification, and DOF...