DSLRUsers.com

hello everyone this is my first post,i am new to DSLR cameras and my knowledge is very limited, i will give some back ground info of my camera,it is a pentax ist D i have three lenses
1, sigma 18-50mm 1:3.5-5.6dc
2.pentax fa 1:4-5.5 35-80mm with aperture ring
3.sigma 55-200 1:4-5.6 dc

yesterday i went to a wedding which was indoors i was using the 18-50 mm lens and the standard camera flash but most of the photos turned out really dark,luckly i was shooting in RAW so i could fix most of them up with PP. i was shooting in manuall mode and i asked the photographer if he new why they were so dark he had a look and said that it is strange the setting were ok ,but he was very bussy and only had a very quick look.
tonight i had a play and still the photos inside were dark these are the settings shutter 1/45 f 4.5 iso 800 with flash
ok here is the twist i used the pentax 35-80 mm and set the apenture ring to f-4 and shutter at 1/180 and flash the photo turned out perfect,now with the same lens put the aperture ring to auto and adjust through the camera they are dark again settings shutter 1/20 f4.5 flash
can some please explain what i am doing wrong or is there an issue with
the camera
thanks zsolt

have you accidently set exposure compensation to a negative value?

thats all i can think of.

grab your manual and look up exposure compensation, it should tell you what it is and how to change it.

hope that helps.

Thommo

I'm not familiar with Pentax system at all, so I'm not sure about the controls and options available.
Do your camera have a flash exposure compensation setting? Does it have front/rear sync curtain setting?

As Thommo said, check about the exposure compensation as well.


Also, how far are you from the subject? Moving too far away may cause bad underexposure with built-in flash.

i have played with it and did not make that much difference

I'm not really knowledgable on the Pentax cameras, however to me it's sounding like the mechanics of the camera body, that controls the aperture blades) may not be working properly.

Do your other lenses work OK if you set the Aperture ring's to their smallest aperture (eg. f22) and use the body to control the setting ?

If this works OK, perhaps it's the lens. If not, then maybe it's the body.

Of course, I am just speculating. Perhaps another Pentax user on the forum may be able to enlighten you as to what may be going on.

Not much help, really

Dave,

I'd have thought that if there was an issue with the aperture rings sticking, we'd be seeing images that were over exposed, rather than under exposed.

Zsolt,

Welcome.

You say that you set the aperture ring to auto, but what were the camera settings? Were they too set to auto, and if so, what mode?

It sounds to me as if the camera may have still been in manual mode, thus leading to underexposed images. Could you please post a couple of the suspect images, along with the relevant EXIF data from them?

The EXIF will tell us exactly what happenned at the moment of exposure, and with that information we should be able to help a lot more.

gstark wrote:Dave,
I'd have thought that if there was an issue with the aperture rings sticking, we'd be seeing images that were over exposed, rather than under exposed.

My thinking was that if the lens was set to it's smallest aperture (say f22) and the camera body wasn't opening the blades as it should, then the images would come out as under-exposed.

Of course I am certainly no camera expert so my theory could be incorrect.

Aussie Dave wrote:

gstark wrote:Dave,
I'd have thought that if there was an issue with the aperture rings sticking, we'd be seeing images that were over exposed, rather than under exposed.

My thinking was that if the lens was set to it's smallest aperture (say f22) and the camera body wasn't opening the blades as it should, then the images would come out as under-exposed.

Of course I am certainly no camera expert so my theory could be incorrect.

Neither am I, nor particularly with the mechanics of a Pentax, but regardless of the aperture setting, the lens will be fully open for TTL viewing prior to releasing the shutter, and it needs to then close down to the selected aperture during the exposure.

If the blades are sticking, I would therefore expect them to be sticking from an already open position.

That's my line of thought, FWIW.

Cheerz.

here is an example of what i mean

Flash used: Yes (manual)
Focal length: 80.0mm (35mm equivalent: 120mm)
Exposure time: 0.011 s (1/90)
Aperture: f/5.6
ISO equiv.: 800
Whitebalance: Auto
Metering Mode: matrix
Exposure: aperture priority (semi-auto)
and

Flash used: Yes (manual)
Focal length: 80.0mm (35mm equivalent: 120mm)
Exposure time: 0.011 s (1/90)
Aperture: f/5.6
ISO equiv.: 800
Whitebalance: Auto
Metering Mode: matrix
Exposure: aperture priority (semi-auto)
the top photo i used the apenture ring which was set to f5.6
the bottom one it was set to auto

Hi Zeddy, I think this is your problem. In both photos you are using aperture priority but in the first photo you are actually setting the aperture manually from the lens so in effect you are using a manual mode and the flash is shooting at full blast as you can see from the blown out highlights on the right.
The second photo, the camera is in a proper aperture priority mode and is trying to work out the proper exposure but is being fooled by the white wall on the right and has reduced the flash power, giving you an underexposed photo.
I could be wrong but that's my take on it.

thanks guys i now have a little more understanding of my mistakes,it shows i have a lot to learn,i have now enrolled in a Digital Camera Workshop.
thanks zsolt

Hello Zeddy,

Phillip's answer sounds like its on the right track. If your camera has spot metering set it to that and focus on the darkest area in the second picture and see if that makes a difference.

Semper Fi,

Bob

Regardless of whether it's in aperture priority or not, the shutter speed and aperture settings were both the same in both photos.

PiroStitch wrote:Regardless of whether it's in aperture priority or not, the shutter speed and aperture settings were both the same in both photos.

But maybe his flash is firing at a different level???

Zeddy, does it work properly with other lenses??

Cheers

MATT

MATT wrote:

PiroStitch wrote:Regardless of whether it's in aperture priority or not, the shutter speed and aperture settings were both the same in both photos.

But maybe his flash is firing at a different level???

Zeddy, does it work properly with other lenses??

Cheers

MATT

That was my thinking, the aperture and shutter speed selected was not enough for correct exposure and was relying on the flash to make up the difference. It is obvious that there is more flash on one photo then the other.

Definitely this does not sound like it's a problem with the aperture controls, shutter, etc.

It's related to the way the Pentax's flash metering works. The flash is being quelched earlier on the dark shots. Unfortunately I don't know the answer beyond that (if it was Canon I could talk you through the details).
Phillip's on the right track, but I don't know enough to even say that the flash is going at full power in the bright shot. Maybe it is, but maybe the issue is more subtle than that.
Definitely I would be checking the flash exposure compensation controls in the camera. When Zsolt refers to "the standard camera flash" we're assuming that means the camera's pop-up flash, but if an external flash was involved I'd also be checking its settings.

Any Pentax experts care to speak up?

thanks for all you suggestions,i have played around a bit more and found that because i was using the aperture ring the camera did not know what the aperture was so it fired the flash(yes the standard pop up flash)flat out.
thanks zsolt
P.S just ordered a canon 30d

zeddy wrote:P.S just ordered a canon 30d

There goes the neighbourhood
I was hoping you'd buy some expensive nikon gear that I could then borrow from you seen that we are in the same suburb

sorry mate was looking at the nikon d200 but was out of my price range and had alot of people say go with canon.

zeddy wrote:sorry mate was looking at the nikon d200 but was out of my price range and had alot of people say go with canon.

Who were you asking?

I know a lot of people who might say to go with Nikon.

The correct advice in fact is neither of the above.

The correct advice is to go into a camera store, and have a play with a few bodies. Play, fiddle, make some images, but decide which one feels right, for you, in your hands.

Ignore any advice to buy Canon, and ignore any advice to buy Nikon: each are equally good, but, as noted above, the correct decision is to buy the one that you feel comfortable with in your hands.

i did go in to the shop and had a play with both and was happy with the canon thats the main reason i went with the 30D.the people i spoke to were not from the forum.
thanks zsolt