[dstan7695]

Ok I got the Pentax K-x, the basic 18-50 mm lens and bought a sigma 50-200mm lens. I bought a lighting kit that includes two black umbrellas and two twin head 90 watt (I think) fluorescent light stands. I bought a strobe flash kit which consists of two strobe slaved non-adjustable flashes with white flash-through umbrellas. I bought a got shoe adapter and have it wired to one of my strobe lights. Had subject app. 3 feet from backdrop last night and camera 12 feet from subject. Put the K-x in auto mode and with settings at factory default images were way to flooded with light. Turned ISO down to 200 and images were much closer but still too bright. Any suggestions? Thanks.

[Ole]

Try Manual exposure mode - decrease the aperture until you get the exposure right. Set the shutter speed to 1/125. Start out with a low ISO.

The camera's flash automation won't work with yur set-up.

[sbphotog]

I don't mean to sound rude, but it sounds like you've rushed into things way to quickly and not really thought about how/what/why and when you might need your gear. Have you ensured that you've read all your documentation properly? Do you know what settings you should be using and most importantly, why you should be using those settings?

[dstan7695]

Thanks ole. But can I use an external flash in manual mode?

[icywarm]

Yes, I do it. Just takes one or two test exposures to get it right... at home like that you shouldn't need to change anything too much after you have it right.... with the expanded ISO Range on the Kx you can goto ISO 100 sans some jpg filters. Turn on the highlight over exposure/underexposure in preview and you should be good to go.

[RioRico]

Ole and sbphotog are exactly right. Read all the documentation (RTFM!) and again and again. Go manual; experiment with settings until you're happy with the results. Write down the settings so you can do it again. I hope you have a patient volunteer for a test subject.

And, depending on the type of portraits you want, you might want a portrait lens. That would be a fast prime, f/1.4 to f/2.0, in the 50mm to 90mm range. For studio portraits, it can be a cheap old manual focus, manual aperture, even screw-mount. Autofocus and exposure automation just aren't necessary for a fixed setup. If you really want auto-everything, the FA 50/1.4 is great. Your zooms are just too slow and sharp for pleasing portrait work.

[dstan7695]

No, I kinda dove in head first without being sure if I could swim on this one! Thank God I found you guys. I actually bought the lighting kit by mistake thinking I was buying a strobe kit. But yes, I am learning as I go on this one in a bid to better recession proof my full-time job with some sidework. I do have some photography experience but its been 12 years and it was large format mamiyas.

I don't mean to sound rude, but it sounds like you've rushed into things way to quickly and not really thought about how/what/why and when you might need your gear. Have you ensured that you've read all your documentation properly? Do you know what settings you should be using and most importantly, why you should be using those settings?

[noahpurdy]

The sync speed of the K-x is 1/160th with external flashes. That means that 1/160th is the fastest shutter you can use and still trigger the flashes.

When working with flash photography shutter speed controls ambient light exposure (The slower the shutter speed the more ambient light) and aperture controls flash light exposure (The smaller the aperture [bigger the number] the less flash light).

Start in manual mode at 1/160th take a test exposure and adjust aperture accordingly. 1/160th won't kill ALL the ambient light but that's as close as you can get.

Do all this with an ISO of 200 for the cleanest image.

You'll also want to read up on the Inverse Square Law of Light so that you can understand how the distance from light to subject can affect the light.

Inverse-square law - Wikipedia, the free encyclopedia

[tibbitts]

I'm not a portrait expert, but I'm not sure why you'd want a 50/1.4 for portraits. I think you'd be hard pressed to get a nose and mouth both in focus at 1.4. I'd think you'd probably want at least f4-5.6, so a typical zoom would be fine.

Paul

[Ira]

With the kx's high ISO capabilities, you can do amazing things with just a simple lamp, the right camera to subject distance, focal length, and background.

So in my opinion and for now, I think your best bet is to just keep the flash stuff packed away until you think you really need it.

There's nothing at all flattering about flash anyway for portraits. It's real tricky stuff.

[RioRico]

I'm not a portrait expert, but I'm not sure why you'd want a 50/1.4 for portraits. I think you'd be hard pressed to get a nose and mouth both in focus at 1.4. I'd think you'd probably want at least f4-5.6, so a typical zoom would be fine.

Short answer: It's traditional.

Long answer: Back in the day (35mm full-frame film etc) the treasured full-face to head-and-shoulders (H&S) portrait lens was the 85/2 or thereabouts. An 85/1.5 was even creamier and more prized, but bulkier. They were sometimes shot wide-open, sometimes stopped down a very little. But they provided a very appealing softness, and creamy bokeh (although that name wasn't used then).

Fast-forward to APS-C times. The closest equivalent of the FF portrait lens would be a 58/2, like a Helios-44. (Pentax made a 58/2, but that was over 50 years ago.) You get the same FOV and a little deeper DOF. A 55/1.8 or 55/1.4 would approximate the DOF even more closely. And a 50/1.4 is damn close on DOF, even if its FOV is a bit wider, more suitable for H&S, but OK closer if stopped down a very little.

For some portraits, you don't want softness. When I shot fellow GIs, it was 35mm Panatomic-X (ASA 32) or 120 Verichrome Pan (ASA 100), orange or red filter, strong light, stopped down so very crease, crag, scar and pore stood out. But 80mm (MF-TLR) or 85mm (Nikon) was still the best focal length. (I could work closer with the slightly slower TLR.) And when I shot their ladies, same film, it was light yellow filter and wide-open aperture.

Your "typical zoom" is just too slow, too sharp, and IQ drops at the extremes of focus and aperture of the 18-55 or 50-200 that OP mentioned. Backgrounds must be further away, or they intrude. There's too much facial detail, which often isn't flattering. Maybe those kinds of shots are all you've seen, all you're used to. But a wider, softer lens (which can always be stopped down as needed) gives a lot more leeway in presenting faces.