Cobra 450AF Pentax dedicated - Any Good?

Hi all,

I've used a Pentax Z-20 for nearly ten years now but have never had a requirement for an external flash.

I've just purchased an *ist DS, and as chance would have it I've also been requested to shoot a wedding in a couple of weeks.

A local camera store has told me that the Cobra 450AF is Pentax dedicated able to be used on all the MZ and Z series cameras and SHOULD (that bit makes me nervous) work on the *ist DS as well.

More importantly the Cobra is £50 which is on-budget for me considering the money I recently spent on the DS...and he has one there which I can take now if I decide that's what I want (no waiting for deliveries from e-bay etc).

Has anyone used the Cobra flashes, will it work with the DS, will it do the job (aparently it is automatic only) or am I better off buying the more expensive Pentax or Sigma alternatives??

Cobra flashes are a good independant make and will work fine on the DS, although you won't be able to use all of the advanced features found on the FGZ series of Pentax guns - but you get what you pay for!
I once had a Cobra (650CD was the model I think) and was very impressed with it indeed and it came with a pro-grip etc. for around £70.

Another very good budget alternative to Pentax is the Centon range from Jessops. I bought the original FH80 (bounce, zoom, swivel head with aux. fill-in flash and AF illuminator. GN30 @ normal zoom, ISO100), following an excellent review in a photo mag. and have been delighted with it for many years. The only negative point in the review was with regard to the build quality but I must say that I personally can't fault it, esp. at the price.
I believe the top model is now the FH95 but the guns are modular, ie. the main body is standard and you buy the hot-shoe mount applicable to your camera body and this also means that you can fit any of them onto the Centon pro-grip.

Centon lenses are cheap and most are of poor optical quality but the flash guns and other accessories are generally very good and represent excellent value for money.

An even cheaper alternative would be to buy a standard flash bracket and cheap gun, which in conjunction with the DS's RTF, might well provide all the illumination you require.
Do bear in mind that a gun mounted on the camera hot-shoe may preclude the use of the RTF!

The FH95 + pro-grip maybe outside your budget (although you could opt for an FH65) but it would be a serious bit of kit and certainly 'look the part' at a wedding

Thanks Kimbo.

I've heard tell of circuitry being damaged (or potentially being damaged) by third party flashes...I don't know if there's any truth to that or if it is just scare mongering in the interrest of the big companies. I wouldn't want my new camera being wrecked for the sake of £50!!!

I'm guessing if it is compatible with the Z series it should work ok with the DS.

There is some truth in damaging the camera's circuitry, but it is usually in connection with very old flash guns. Some had very high trigger voltages. If you put a multimeter across the chassis and centre pin you'd see a very high value. Can't remember which guns, but think some of the old Metzs were guilty of this. It stems from the days when cameras were mechanical and the flash was triggered by shorting the two pins together.

From a safety point of view such high voltages are "no go" (just try putting a wet finger across the pins ). So, if the flash gun has a CE marking on it, it almost certainly has a low trigger voltage and will be fine

Matt

My FH80 works perfectly on my SFX and Z1-P, I haven't tried it yet on my *istDL but can't imagine that there'd be any problem.

Good point though and always worth considering

The old Vivitar 287 guns had a voltage, I believe, of several hundred volts, compared to the modern average of around 3 or 4 volts. This is because the hotshoe trigger circuit was used by the flash as part of the flash discharge circuit. In other words, when the flash fired, the whole lot was pushed through the camera.

This is how they used to do it, and cameras were designed to handle it.

Many modern cameras have a low flash voltage tolerance, but a credible source has said that even modern Pentax cameras can tolerate voltages as high as 400 volts.

To be on the safe side, just avoid very old guns and very cheap guns. If you have a digital voltmeter, measure the potential difference across the flash contacts (the main one in the centre, and the earth).

G

Thanks for the assistance everyone.

I bought the Cobra yesterday afternoon, and it works just fine with the DS. After an hour or two spent experimenting I don't know why I never bought an external flash before...I'm quite delighted with the new possibilities it's opened up.

Once again...thanks for the helpful info.

I'm glad you're pleased with it, did you buy an off-camera flash bracket or pro-grip for it?

It may not be possible to use the built-in RTF when the Cobra is mounted on the camera and you'll need a hot-shoe sync lead but it will make the whole system more flexible. It can be very effective to bounce the main flash and use the RTF for fill-in.

An SLR's hot-shoe is normally positioned on the camera's penta-prism but this can lead to harsh / flat lighting and severe red-eye. Moving the flash away from the centre-line of the camera (directly above the lens), helps to reduce these adverse effects and produce more pleasing results.

The SF and Z series 35mm SLR's were designed with the hot-shoe positioned above the hand-grip and I think it's a pity that later models have reverted to the more traditional layout.