new pentax

[shed301]

hi,
I've just purchased a new k200d and already struck problems

i'm in manual mode and i've taken a few pics with it already. I'm looking at mostly doing landscape photography and taken pictures of rc cars which requires a fast shutterspeed, However the bigger the shutterspeed ,ie: 150 upwards the pictures tend to go more darker and darker. when i'm actually on 1/4000 i virtually can't see anything



settings
1/125 shutter speed
50mm lens
AP - F5.6
manual exposure
W/B - cloudy
ISO - 200



settings as above apart from the increase to 1/2000th of a second



this time it's 1/4000th of a second

all f-stops are the same as the lens only goes down to that far... it's the standard 18-50mm lens that came with the camera..... is this right or have i drastically manage to stuff things up??

thanks

[rfortson]

If you're in manual mode, and you're increasing the shutter speed, all you're doing is reducing the amount of light that enters the camera. Hence your progressively dark shots. You need to open the aperture by a corresponding amount to let the same amount of light in and get the proper exposure.

If you just want to adjust the shutter speed to freeze cars and action, put it into Tv mode. This will allow you to set the shutter speed you want and the camera will automagically adjust the aperture so you'll get the proper exposure (within reason - it's not a miracle worker).

I highly recommend reading "Understanding Exposure" by Bryan Peterson. It's a great guide to the relationship between shutter speed, aperture, and ISO.

[Canada_Rockies]

You probably have not changed the ISO to allow the faster shutter speed. Every time you double the shutter speed, you need to open the lens one stop more (8 > 5.6 for example). If the lens is wide open (smallest aperture number, biggest hole in the middle of the lens), there is a maximum shutter speed at every ISO. So doubling your ISO will allow you to double the shutter speed, compared to a normal exposure.

Search the forum for the word "exposure" and you will find a lot of help.

[dosdan]

I just tried outside with a 18-55 Mk 2 lens on a K100D Super. At ISO 200 & F5.6 in Av mode, the shutter speed varied between 1/250s to 1/750s depending on whether the sun was obscured by a cloud or not. I suspect your shutter time is right for a cloudy/overcast day.

With a landscape you'll probably be shutting the aperture down to F8-F11 to get enough DOF. I'd suggest a tripod.

Going to a prime with a bigger aperture will be the cheapest way to cover your R/C cars. For example with an old Pentax-M 50/F1.7 (manual exposure & manual focus - cheap 2nd hand) I was getting 1/180s at around F5.6/F6.7 (markings are a bit hard to determine) & 1/1500s at F1.7. The trouble with F1.7 is the shallow DOF & lower sharpness at max. aperture (although the F1.7 lens is not too bad wide open, it's better at F2.8), so the widest usable aperture will depend on the situation.

Dan.

[HGMonaro]

sounds like you're not making the requireed adjustments to aperture or sensitivity (iso)

assuming you want the same exposure, everytime you change the shutter speed you need to make a change to aperature or the sensitivity.

since your 1st pic is there-abouts ok, equivalent exposures at 1/4000 sec would be f1.4 @ 200iso or f5.6 @ 3200iso

[chrisman]

It's time to learn about the relationship between Shutter Speed, Aperture and ISO.

Apart from the advice already given, you might want to check out these sites as starter:

SR Photography - Digital Basics - Shutter Speed - Aperture - ISO

Understanding exposure: shutter speed, aperture, and ISO | Photodoto

There are plenty of others if you care to look.

Good luck!

[dosdan]

The sites Chris mentioned are good, but you may learn more easily through twiddling the dials in an exposure simulator and immediately observing the result, rather than by reading text. Try:

www.photonhead.com

particularly

www.photonhead.com/simcam/

Dan.

[shed301]

awesome guys !. your help has been terrific, and i can see myself doing a lot of reading....canadian rockies. your where right on the money. after reading what you said i went out to test and bingo.. i had pics at 4000.. after coming from a P&S i've finally gone DSLR which suits me as i have a pentax k mount film camera.... so the lens from that fit on mine with no issues at all...

rfortson: that book is actually on the way..... thanks

I just got to get familiar with the various F stops and ISO settings now.... actually started to write down the various settings in a notebook for future reference

Once again thanks guys

[Canada_Rockies]

Originally Posted by shed301

awesome guys !. your help has been terrific, and i can see myself doing a lot of reading....canadian rockies. your where right on the money. after reading what you said i went out to test and bingo.. i had pics at 4000.. after coming from a P&S i've finally gone DSLR which suits me as i have a pentax k mount film camera.... so the lens from that fit on mine with no issues at all...

rfortson: that book is actually on the way..... thanks

I just got to get familiar with the various F stops and ISO settings now.... actually started to write down the various settings in a notebook for future reference

Once again thanks guys

That notebook is a good idea. I suggest it be small enough that you can take it into the wide world with you whenever you carry your camera.

[JohnV3]

There should be an exposure meter in the viewfinder when in manual mode. You can immediately tell if your exposure setting is under or over exposed and then make adjustments accordingly.