[Wheatfield]

Something that has to be brought to the table for anyone who is thinking of buying into a camera system for professional use is equipment reliability.
In this regard, Pentax looks like a great big, wet turd.
The OP would do well to research the number of different problems the K5 has put it's owners through before deciding on a camera system to buy into as a money earning tool.
Nikon brings a better flash system to the table for sure, but they also bring more robust equipment.
Pentax brings twitchy, and undependable equipment, so the equipment investment is going to be much greater.
If I was to get back into professional wedding photography again, there isn't a snowballs chance in hell I would be looking at Pentax.
Not right now, anyway.
The lenses are nice, though with the SDM lenses, this must be tempered with when they work, and the K5 is, at best, a work in progress.
With Nikon, you should have two of everything, and perhaps a third body.
With Pentax, you should have 3 of everything (if you are using SDM zooms), and I don't know how many bodies I would feel comfortable with having to be sure I was covered. If it was K5s, I would want at least 4 of them, just to play the odds that one would be working at any given time.

[elho_cid]

Wheatfield: How many cars do you have? How many houses?
This is quite a paranoic standpoint that of yours. Or maybe you are unusally clumsy, I don't know.

But jokes aside, my K-5, before I upgraded to fw1.04 froze 3 times, only when using manual lenses or in liveview. I use neither of these for weddings. I had no single problem with newer FW and many had no problem regardless of FW version. It is irresponsible not to have a second body for wedding, I agree. But 4?

[Anvh]

hmm i wonder how the 645D will do with weddings.

[Wheatfield]

Wheatfield: How many cars do you have? How many houses?
This is quite a paranoic standpoint that of yours. Or maybe you are unusally clumsy, I don't know.

But jokes aside, my K-5, before I upgraded to fw1.04 froze 3 times, only when using manual lenses or in liveview. I use neither of these for weddings. I had no single problem with newer FW and many had no problem regardless of FW version. It is irresponsible not to have a second body for wedding, I agree. But 4?

I've had unreliable cars leave me stranded, and I've made a pretty decent income recently fixing people's unreliable houses.
Do you have another point to make?
When I shot professionally with Nikon, I never felt that the camera would let me down unless I did something stupid. With Pentax, I never felt that way, and the number of different problems the K5 has shown is not exactly confidence inspiring.
Having the camera jam up so that you miss the ideal moment of a pretty sunset is one thing, having it happen during the ring exchange is another thing entirely, and freeze ups are just one of several things the K5 is capable of doing to it's users.

[Anvh]

Every camera has their own problems these days.

The D700 is leaking some grease for example.
Grease Spots on Nikon D700 - Fine art photography forum

The 7D was pretty dodgy also and the 1D mark III is also leaking oil, had abnormal mirror operation and focus problems and that for an high-end pro camera...

Maybe we should just go back and shoot with film again, much more reliable than all those electronics.

[veezchick]

If I had to start over knowing what I know now....I'd never have gone with Pentax. Lack of Pocket Wizzards, battery packs for flashes, wireless TTL etc......Buy yourself some SB900's, Pocket Wizzards and live life. And we didn't even cover the auto focusing capabilities between the 2 companies....

I'm with Deiberson, here. I love my K10D and K20D, but the Pentax off-camera flash limitations are a drag, as is the poor Al Servo tracking focus. And noise. Oh, so much noise at 400+ ISO. Luckily, most of the stuff I do these days does not require off-camera flash above 1/180th, but there are those times I have to leave the flash (gasp) on the camera for HS. And I'm not interested in a cheesy 9.5' sync cord. I have a lot of work-arounds, but haven't figured out how to hack 1/180+ wirelessly (if anyone has, please share your wisdom). Now I'm stuck in that 'how much more should I invest in Pentax gear' vs just buy a Nikon system and get on with it.

[noahpurdy]

If you want any kind of decent TTL flash, don't pick Pentax. The 540 costs damn near as much as an SB-800 and it's built like a toy. P-TTL is accurate about 75% of the time and it's not robust at all.

[Anvh]

I'm with Deiberson, here. I love my K10D and K20D, but the Pentax off-camera flash limitations are a drag, as is the poor Al Servo tracking focus. And noise. Oh, so much noise at 400+ ISO. Luckily, most of the stuff I do these days does not require off-camera flash above 1/180th, but there are those times I have to leave the flash (gasp) on the camera for HS. And I'm not interested in a cheesy 9.5' sync cord. I have a lot of work-arounds, but haven't figured out how to hack 1/180+ wirelessly (if anyone has, please share your wisdom). Now I'm stuck in that 'how much more should I invest in Pentax gear' vs just buy a Nikon system and get on with it.

How fast is Nikon flash sync, 1/250 right?
We are talking about half a stop then, not really worth the effort i think...

If you want a darker background then maybe using a more powerful flash with an ND filter on your lens is an option.
I've already seen several pro's using a VARI-ND with strobist work so that they can use the lens at the widest aperture in full sun light.

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[kenyee]

If you want any kind of decent TTL flash, don't pick Pentax. The 540 costs damn near as much as an SB-800 and it's built like a toy. P-TTL is accurate about 75% of the time and it's not robust at all.

Have you done back to back comparisons?
I was shooting a fashion show last weekend and glanced over as others w/ Canon/Nikon gear reviewed their images and saw a lot of exposure variation (wayy over and under) compared to what I was using (Nikon flash in A mode on my K20D)...
I was surprised to say the least...thought I was going to see the magic Nikon super TTL system nail most of the exposures...

[D4rknezz]

Pentax controlled wireless system for me is called Elinchrom Quadra....with their wireless triggers and grouping and all that.
Personally, I like my lights. And in weddings, especially during the first part of weddings, its difficult to drag strobes around. So you are left with AF540 on your camera. It can be done, but I am left curious about other systems. If you are in love with Nikon and or canon's lighting system...I'd say you would hate Pentax's. Always felt left behind by 3rd party radio trigger makers too. Dont get me wrong, I love my pentax to death, but once 5DMK 3 is out, my K5 is my backup system. You can make it work. My next wedding I am bringing 2 or 3 strobes to light the hall. 1 Quadra, 1 alienbee, and 1 Elinchrom style Rx600. Heavy, heavy lighting gear there....

Also, what Wheatfield said.

[veezchick]

How fast is Nikon flash sync, 1/250 right?
We are talking about half a stop then, not really worth the effort i think...

If you want a darker background then maybe using a more powerful flash with an ND filter on your lens is an option.

Bigger flash with ND on lens is one of the work-arounds I mentioned. Users can hack more than 1/250 HS out of Nikons. Won't go into that here.

[noahpurdy]

Have you done back to back comparisons?
I was shooting a fashion show last weekend and glanced over as others w/ Canon/Nikon gear reviewed their images and saw a lot of exposure variation (wayy over and under) compared to what I was using (Nikon flash in A mode on my K20D)...
I was surprised to say the least...thought I was going to see the magic Nikon super TTL system nail most of the exposures...

Shooting TTL in an ever-changing environment like a fashion show is certainly going show a lot of exposure variation; it's the nature of the beast. When speaking of the accuracy of P-TTL, I can set up a scenario with no changes and 7/10 shots will be properly exposed.

In terms of it's robustness you are unable to control the flashes from the camera when shooting wirelessly and exposure compensation for the flashes / camera exposure do not work in an intuitive manner with Pentax.

[FuzzyOne]

If I was in your shoes, I would go with Nikon. Listen to the previous posters, there are many limitations to the Pentax system. I am always learning something new with flash, but Pentax has not reached the refined level of Nikon.

[intjonmiller]

I decided to move forward despite some of the warnings here. Just did my first shoot yesterday with a K-r to try out the system. Only flash I used (minimally) was fully manual. But I discovered something I REALLY don't like: Not only does the flash not sync above 1/180, it won't even fire!! Somehow I hadn't caught that in my reading. (It was probably mentioned and I just missed it.) One of the ways to "hack" faster shutter sync is when you're shooting with only part of the frame exposed by flash. So you position the part of the frame that is syncing over that area and rely on the ambient for the rest, or just shoot a little wider than you want and crop out the part that didn't sync. But Pentax seems to have made that impossible, unless there's a custom function somewhere that I'm missing?

I also tried with 3 different kinds of wireless triggers. Same problem. Not cool. But now I really like the quality I'm getting out of this camera (which, in turn, makes me want the K-5 even more...) which just makes me even more irritated that Pentax is so far behind the times with flash. Maybe something wonderful will happen with the new Ricoh arrangement to make our wildest dreams come true...

[elho_cid]

It is true, not only 1/180 is fastest possible with x-sync, but even HSS is blocked with manual (non-A) lenses. Pentax is really not the best option for strobist work.