[Unregistered User 8]

Hi folks. I am considering the purchase of a Sigma EM 140 DG ring flash for my macro images, but I am unsure as to whether the extra weight on the front of the lens would put too much strain on the auto focus ( screw drive shaft or motor.) I have a K-3 and the 100 2.8 WR, and sometimes use the 1.4X rear converter as well. Not all my shots are AF, but I would like some assurance from you knowledgeable bunch that it is not a problem. Any help or comments greatly appreciated. Thanks.

[SpecialK]

...extra weight on the front of the lens...

I have a similar looking Bowers ring light. The ring portion is very light - I would not worry about the weight.

Coincidentally I have not ever used it. I had it out just the other night to test it with my current system. I have the 2 adaptor rings and neither fits any of the lenses I have :-( I guess I need a couple new adaptors. I just held the unit next to the lens. It has possibilities I should investigate.

[Unregistered User 8]

I guess I need a couple new adaptors.

Thank you for the speedy reply SK. As the ring adapters screw into the filter thread of the lens, I wonder it we could just use step-up rings to use with the existing ring supplied?

[SpecialK]

Thank you for the speedy reply SK. As the ring adapters screw into the filter thread of the lens, I wonder it we could just use step-up rings to use with the existing ring supplied?

If you are going to get a step up (or down) ring, I'd go from the flash to the lens without the intermediate ring. I need a 49 ^ 52 for my 50mm lens, and a 67 v 52 for the macro 100.

[pathdoc]

I have the Pentax AF080C, which I generally use with the 35 Lim Macro, and occasionally with non-macro lenses on A-contact extension tubes (thank heavens for the almost-Pentax-standard 49mm filter size). The issue is bulk as much as weight, but it isn't much; most of both is in the flash control and power module on the hotshoe.

While I don't use the 100 very much, I would have no issue putting a ring flash on it; one is generally supporting the lens barrel for such uses anyway, since the main use of a ring flash IMO is to enable very narrow apertures when bug and slug hunting without a tripod.

[BrianR]

Interesting, I always just assumed you'd attach a ring flash to the dfa100mm via the hood mount(*see below). I'll be interested to hear what combos people have used directly on the filter thread with autofocus. I know the WR version of the dfa100mm is sturdier than my non-WR one, but I'm hesitant to attach much weight without supporting the extended barrel, which pretty much rules out AF. Even if it functions without a hitch, it seems like having the bulky light on the end whizing forward and back would be annoying?


*The Pentax 160FC ringflash comes with an adapter tube for mounting to the body of the lens:

You Tube

You Tube

[pathdoc]

The trick here is that AF often isn't that useful in macro; once you have hit the approximate plane of focus, you rock back and forth in manual until the object of most desire is acceptably sharp. Flash plus narrow aperture takes care of the rest. You aren't whirring back and forth an awful lot, and the D-FA 100WR has quick shift anyway. Any AF touch-ups are minor.

[BrianR]

The trick here is that AF often isn't that useful in macro;

I disagree and I use it pretty frequently, so your trick is indeed tricksy.

And yes, I have years of practice hitting critical focus by moving the entire camera/lens assembly as a unit by hand (and more recently via a rail) and I reckon, by right of passage through innumerable failures, I've gotten pretty good at it. But I'll take AF as an option in the toolkit for when it's applicable, and for me that's regularly. YMMV.

[wombat2go]

I have the Pentax AF080C,

Disaster here, I just broke the shoe mount off my vintage AF080C power unit.
I had it on the ist ds and it must have toppled sideways on the table.

[pathdoc]

Disaster here, I just broke the shoe mount off my vintage AF080C power unit.
I had it on the ist ds and it must have toppled sideways on the table.

You have my sympathy - that situation is in some ways worse than dropping a brand new K-1, since the K-1 is at least still in production while analogue TTL stuff is a pearl of great price.

[Unregistered User 8]

While I don't use the 100 very much, I would have no issue putting a ring flash on it; one is generally supporting the lens barrel for such uses anyway, since the main use of a ring flash IMO is to enable very narrow apertures when bug and slug hunting without a tripod.

Thanks for the feedback mate. Much appreciated.

*The Pentax 160FC ringflash comes with an adapter tube for mounting to the body of the lens:

Thank you Brian. The Pentax 160 ring flash mounts to the lens differently to the Sigma. The Sigma uses a metal adapter ring very similar to a step-up ring the screws into the filter thread of the lens and the mounts into the ring flash housing. The rings come in different sizes to suit the lenses. I much prefer the Pentax flash system with the collar, but at $835 AUD new, and no 2nd hand copies available, it is out of my budget.

Disaster here, I just broke the shoe mount off my vintage AF080C power unit.I had it on the ist ds and it must have toppled sideways on the table.

OUCH !! Sorry to hear that.

[SOldBear]

I've been using my Sunpak DX-8R and Sunpak DX-12R with Pentax 50mm macro and 100mm macro (WR version). I don't notice any problem with autofocus.

This is not related to the thread, but it may help somebody: Ring flash quick release.

[TER-OR]

I have also not had troubles with the FA100 macro and Sunpak DX-8R. The weight is all in the controller/power unit perched on the hotshoe. The strobe itself is pretty light.
Of course the Sigma may be different.

I am also evaluating a 1.4X teleconverter - and it DRINKS light. Without I'm using the ring flash in manual at 1/8 or 1/4 - but now it's at least 1/2 power with the TC.

[Unregistered User 8]

I've been using my Sunpak DX-8R and Sunpak DX-12R with Pentax 50mm macro and 100mm macro (WR version). I don't notice any problem with autofocus.

Thanks SB for the feedback. Much appreciated.

I have also not had troubles with the FA100 macro and Sunpak DX-8R. The weight is all in the controller/power unit perched on the hotshoe. The strobe itself is pretty light. Of course the Sigma may be different.

I am also evaluating a 1.4X teleconverter - and it DRINKS light. Without I'm using the ring flash in manual at 1/8 or 1/4 - but now it's at least 1/2 power with the TC.

Thank you Terry for your input. The added information regarding the 1.4X rear converter is most welcome.

[Unregistered User 8]

Thanks to all who responded to my question. You have helped me make the decision to get the Sigma flash. Much appreciated advice.


EDIT - It is a wonderful addition to my kit, I can highly recommend this ring flash.