The Official Newbie Questions Thread

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TheWolf

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Hello everyone, I suddenly feel guilty invading the forum with questions. Therefore, the point of this thread is that beginners can ask questions here - so when someone knowledgabe is feeling charitable, they can pop in and donate a few bits of knowledge at their own time.

Ok I will start off first. On my camera, why even in manual mode, I can't adjust the f-value to less than 4.2?
 
Ahh probably. It's AF-S Nikor 18-55mm 1:3.5-5.6GII ED lens. How do you read this? :s
 
What was the focal length of the lens when you got it to 4.2?

at the 18mm end you'll get to 3.5 and at the long end you'll be down to 5.6


Asking Questions is what we're here for :thumbs:
 
digitalfailure said:
What was the focal length of the lens when you got it to 4.2?

at the 18mm end you'll get to 3.5 and at the long end you'll be down to 5.6


Asking Questions is what we're here for :thumbs:
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Ah you are right. I forgot that focal length affects the aperture :) Cheers
 
Just to clarify ... it doesn't have to affect the aperture. It's only on the cheaper (probably fairer to say less-extortionate) lenses where they vary like that.

The expensive lenses normally have constant aperture, e.g. the 70-200mm f4 L is a zoom lens where changing the focal length won't change the maximum aperture, but you'll never be able to go over f4.
 
I'd like to ask if the glossary which i found on the extras menu will be fixed soon. there are so many things i find i need to check. especially abbreviations. :)
 
Just a question about flash and aperture. Lets say I shoot the same photo - one with a small aperture F3 and one with a higher one F20. Now because F20 is so high, i probably need flash, but it looks horrible with flash. Is the only way to decrease the shutter speed?
 
TheWolf said:
Just a question about flash and aperture. Lets say I shoot the same photo - one with a small aperture F3 and one with a higher one F20. Now because F20 is so high, i probably need flash, but it looks horrible with flash. Is the only way to decrease the shutter speed?
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correction: f3 is a big aperture, f20 is a small aperture

if you are trying to avoid the flash the alternatives are:
- decrease the shutter speed to make it open for longer (risks motion blur of the subject. You can also get blurring of the total image due to camera shake, but a tripod or improvise by leaning the camera on a solid surface can help with that)
- open the aperture (also reducing the depth of field, but if thats an issue you could possibly move further away to increase the depth of field again as the depth of field is shorter when closer)
- increase the film speed (sensor sensitivity on digital) to a higher ISO (and risk grainy image if you go too far, but depends on conditions and not always a big problem)
- open the curtains/door or switch on the lights, or ask everybody to step out into a brighter area :D
- use flash with a bounce (use flash with a swivel head aimed at ceiling or walls or umbrella or big flat card to side or behind you to provide a greater lighting area, offset lighting and less harsh shadows) or a flash diffuser and/or off the camera to get rid of the harsh shadows and direct lighting
 
White. I was photographing room, and under normal lighting, everything seems sort of creamy yellow and sepia. I don't get that with flash. But if I don't use flash, i can only decrease shutter speed to let me in more light right? Or I could increase ISO...is that right?
 
Thanks a lot wookie. Also I have been wondering why people use remotes for tripods? Are they scared that touching the shoot buttom will cause the camera to shake? =)
 
that is correct wold it can cause the camera to wobble, they also use mirror lockup to ensure that no vibration or movement occurs that will blurr the image, a remote shutter is exactly the same as a cable release on a 35mm film camera, allows you to not touch the camera when releasing the shutter. the other advantage of the remote shutter release is that you can set the camera up away from yourself and thus have less chance of disturbing whatever your shooting (i.e insects etc in a macro shot.
 
TheWolf said:
I was photographing room, and under normal lighting, everything seems sort of creamy yellow and sepia. I don't get that with flash.
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that's probably because of the "white balance".

Quick explanation (honest):

human vision processing is amazing and corrects the colours that we actually see into the colours we expect. The reality is that the actual colours reflected back from objects are dependant on the light falling on them, different light sources (plus any reflections off walls or other objects) give out different spectra of light which taints the colour of objects viewed in that light. Our vision processing considers the ambient light spectrum and does a rapid correction of the image to return it to a daylight setting.

Cameras (film or digital) cannot do that, they just record the actual colours of the objects in the image as they really are.

Therefore we have different types of film and filters to suit the ambient light conditions, or in the case of digital a "white balance" setting which can be applied on the camera, or if you are using RAW files you can apply the whte balance setting manually afterwards. There is usually an Auto White Balance setting ("AWB") but cameras are not as smart as a few million years of evolution and can't always get it as good as we would like.

If you are photographing indoors using artificial lighting you may like to play with the white balance setting. There is usually a "Tungsten" and a "fluorescent" setting which you should use.

Note that white balance can also change outside due to bright sunlight, cloud cover, shade, or even a lot of foliage.

The light from flash has a spectum that is equivalent to normal daylight, its also much brighter than any ambient light, so flushes the image to our perceived daylight normal
 
What do you mean by 'rapid correction of the image to return it to a daylight setting'? I understand most of what you say, in explaining why what you see isn't what you see from the camera. Thank you :)
 
TheWolf said:
What do you mean by 'rapid correction of the image to return it to a daylight setting'? I understand most of what you say, in explaining why what you see isn't what you see from the camera. Thank you :)
Click to expand...

its all done by the eye-brain thing, what YOU see is not exacty what you SEE. The eye-brain processing does an instantaneous white balance correction, to make what you have in front of you appear in your brain as if it was in normal daylight, truly amazing stuff.

You can catch it out but it takes a bit of effort, if you can look very carefully at a particular scene with different local light sources you will notice the differences, also if you try colour matching between different light (indoors/cloudy/sunshine) then your colour perceptions are very slightly different.
 
Woah so from what I read, under a cloudy sky, as you said what I see isn't really what I see, but is a result of auto-white balance correction. Very weird!!
 
if you want to get it really spot on, then use an "18% grey card" in the lighting you are dealing with.
2 ways to use it:
- a lot of cameras allow you to do a custom white balance, usualy involves taking a picture of the grey card with a menu function chosen (read the manual), this sets the "custom white balance" on the white balance menu to suit those ambient light conditions, just select custom WB for those shots
- just take a shot including the grey card in it (in the lighting conditions for that sequence of shots), and then when you load the photos onto your PC, go to your editing software and you should find (probably in levels or colour) a pipette symbol, click on the pipette tool symbol then click on the grey card, it will take a colour reading from the card and apply it to the whole photo. There should be a way to save that white balance and apply it across a group of photos.

Grey cards available from Jessops, http://www.jessops.com/Store/s9652/0/Grey-Cards/Jessops/Grey-Card-8-x-10in/details.aspx?&comp=n

also somebody on TP once mentioned that the grey interior on Lowepro bags is 18% grey!

if you're desperate or just want to test the idea then a piece of white A4 printer paper will get you close, but not as reliable.
 
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