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Wolfie's learning thread
http://www.x404.co.uk/forum/viewtopic.php?f=17&t=16139		 Page 1 of 1
Author:  cloaked_wolf [ Sat Mar 24, 2012 11:11 pm ]
Post subject:  Wolfie's learning thread
Rather than post multiple threads asking lots of questions, I figured I'd post in this one.

I've been reading "From snapshots to great shots" by Jeff Carlson. Learning a lot about the G12, things I can do. The big thing for me has been to go into manual mode and control aperture, ISO and shutter speed independently. I'm still trying to get the hang of things. Today, bored and supposedly studying, I took a few pics of my watch. The lighting conditions remained the same throughout. I tried to keep the ISO low to minimise noise. What I'd like help with is analysing what I'm doing wrong and why. I've reduced the photos from RAW to 800x600 JPEG but if it helps to use a different format, please advise me.


This is taken in fully automatic mode for comparison:
Image


Here's my first shot:

Image
ISO 100; F2.8; 1/80

Looks very colour cast so I changed the white balance to automatic:
Image
ISO 125; F3.2; 1/8

This is the camera's HDR mode:
Image
ISO 800, F3.2, 1/20

Image
ISO 125, F2.8, 1/8


What I'm trying to do is take a pic similar to the first one. But if I switch to manual, I just get the watch screen in the way. Also, despite manual white balance adjustment (focussed on a white magazine cover), there's a slight colour cast which I can't get rid of. I'm also losing sharpness which the first pic has in the bezel numbers.

How can I get the camera to look "through" the glass screen? The first pic, because it was "automatic" was shot in JPEG, the rest were in RAW. Is this the camera's processing that's sharpening and correcting the pictures?
Author:  belchingmatt [ Sun Mar 25, 2012 5:42 am ]
Post subject:  Re: Wolfie's learning thread
cloaked_wolf wrote:
What I'm trying to do is take a pic similar to the first one. But if I switch to manual, I just get the watch screen in the way.... I'm also losing sharpness which the first pic has in the bezel numbers.


I've created a quck summary of the variable EXIF data from your shots.

Code:
img   f   s   iso   foc lng   meter   sub dist   flash   WB
1   3.5   1/60   160   16mm   pattern   230mm   F, A, RE   auto
2   2.8   1/80   100   6mm    pattern   120mm   F, Comp, RE   manual
3   3.2   1/8    125   10mm   pattern   170mm   No, Comp   auto
4   3.2   1/20   800   10mm   pattern   190mm   No, comp   auto
5   2.8   1/8    125   6mm    pattern   120mm   No, comp   manual


I wish it were as simple to say that you tweaked the aperture in one shot, tweak it back and all will be fine, but as you can see there are other differences. Depth of field changes with aperture, but also with subject distance. Also from the photos, the camera and subject orientation changes, and this will affect the light being reflected off the watch glass and what the camera chooses to focus on. Using a smaller aperture (larger f number) should give you more sharpness across the whole subject, but will also increase shaprness of other possibly distracting objects in the frame.

To really understand each camera setting variable I would suggest limiting as many of the other variables as possible by using a fixed subject, camera and lighting. Once you have a better undertanding of their effects then have a look at lighting etc.

cloaked_wolf wrote:
Also, despite manual white balance adjustment (focussed on a white magazine cover), there's a slight colour cast which I can't get rid of. I'm also losing sharpness which the first pic has in the bezel numbers.


You could try using white A4 that wouldn't reflect as much as a glossy mag. Ideally you want to fill as much of the sensor/viewer/lcd with your white balance card as possible, but of course still letting light through the lens. I doubt a magazine cover has enough white and you could be affecting the balance by either having it too close to the camera, or by colours other than white being sampled. If you can use the balance card just in front of the subject so it has the same lighting.

cloaked_wolf wrote:
How can I get the camera to look "through" the glass screen? The first pic, because it was "automatic" was shot in JPEG, the rest were in RAW. Is this the camera's processing that's sharpening and correcting the pictures?


The best way to look through glass when you have no option to change lighting or move the subject is to use a circular polarising filter.


*awaits patiently to be corrected by those with greater understanding*
Author:  big_D [ Sun Mar 25, 2012 7:53 am ]
Post subject:  Re: Wolfie's learning thread
I agree with Matt, set up a scene and just experiment with the different settings. The best way would be to use an artifical light source, as you can then discount changes in the sun and other lighting effects between shots - using a tripod would also help, as you can guarantee, that only the settings have changed between shots. Once you have the basics down and understand the differences, you will be able to experiment more quickly in natural light.

I'm guessing the deeper depth of field on the automatic shot helped make the numbers sharp. I get very annoyed with autofocus. I grew up in the days of manual focus and, to be honest, for a lot of my photographs, as oppsoed to snapshots, I tend to switch off the autofocus and use manual.

I had to document the construction of a waterproof touch terminal a couple of weeks back and due to the odd angles and cr*p lighting, I think I took about 2/3 of the pictures using manual focus. That way, you have the full control over the image.

Depending on what I am doing, I'll often use apeture priority or shutter priority, instead of fully manual mode. Like you, I also tend to use low ISO (low for a digital, I can remember when ISO400 was a reasonably fast film and you didn't want to go to 800, if you could help it. That said, the lenses on my Canon are a lot darker (F2.4 or worse). The old lenses on my Praktica is better, F1.8 and F1.4, and they were cheap lenses.

My girlfriend went to a function held by the wholesaler that suppliers the kitchen where she works. She took my little Canon Ixsus with her. The photos all had a very yellow cast. That set of pictures was the first, where I have really done a lot of very aggresive post work with Lightroom.

Edit: One of my favourite photography books is "My Way With a Camera" by Victor Blackman. It is very well written, by somebody who is enthusiastic and doesn't get bogged down in the details, he talks about the practicalities and how to get good shots in difficult circumstances, without worrying too much about specific apetures, shutter speeds etc.
Author:  cloaked_wolf [ Sun Mar 25, 2012 9:23 am ]
Post subject:  Re: Wolfie's learning thread
belchingmatt wrote:
I've created a quck summary of the variable EXIF data from your shots.

What do the F/A/RE/auto/comp mean? The flash was manually disabled in all shots.

belchingmatt wrote:
I wish it were as simple to say that you tweaked the aperture in one shot, tweak it back and all will be fine, but as you can see there are other differences.

I often found that if I reduced the aperture, the image on the screen would darken. Hence had to adjust shutter speed (over ISO) to improve the exposure.

belchingmatt wrote:
the camera and subject orientation changes

It was a bit difficult as I basically put the camera on the bed and used the timer to take the shots, minimising camera shake. I appreciate there will be angles which minimise the reflection off the watch glass, and others that maximise it.

belchingmatt wrote:
Using a smaller aperture (larger f number) should give you more sharpness across the whole subject, but will also increase shaprness of other possibly distracting objects in the frame.

Which is what I was trying to avoid by going for the greatest aperture. I wanted only the watch in focus, but I accept that this means that some bits of the watch will still be blurry.

belchingmatt wrote:
You could try using white A4 that wouldn't reflect as much as a glossy mag.

Makes sense. I didn't consider the glossy cover would be too reflective. I've seen people use exposure cards in part of a pic eg shirt pocket of a subject, use it and then either remove it or photoshop it out.

belchingmatt wrote:
The best way to look through glass when you have no option to change lighting or move the subject is to use a circular polarising filter.

Excellent. I have one of them. I shall tinker.
Author:  cloaked_wolf [ Sun Mar 25, 2012 9:28 am ]
Post subject:  Re: Wolfie's learning thread
big_D wrote:
I get very annoyed with autofocus. I grew up in the days of manual focus and, to be honest, for a lot of my photographs, as oppsoed to snapshots, I tend to switch off the autofocus and use manual.

I wish I could do the same. The G12 is a compact camera, albeit very capable. It has a limited "manual focus" that's controlled by a dial on the back of the camera.

big_D wrote:
Edit: One of my favourite photography books is "My Way With a Camera" by Victor Blackman. It is very well written, by somebody who is enthusiastic and doesn't get bogged down in the details, he talks about the practicalities and how to get good shots in difficult circumstances, without worrying too much about specific apetures, shutter speeds etc.

Will have a gander.



I understand there's a magic triangle between ISO, aperture and shutter speed, and as long as you keep within the triangle, the exposure will always be the same. The size and shape of the triangle will depend on circumstances.

Thanks for the advice guys. I'll post up some more pics later this week, when I get a chance.
Author:  belchingmatt [ Sun Mar 25, 2012 10:13 am ]
Post subject:  Re: Wolfie's learning thread
cloaked_wolf wrote:
belchingmatt wrote:
I've created a quck summary of the variable EXIF data from your shots.

What do the F/A/RE/auto/comp mean? The flash was manually disabled in all shots.


It looks like it may not have been disabled in all shots.

F A RE = Flash on Auto, Red Eye Reduction
F C RE = Flash on Compulsory, Red Eye Reduction
No = Flash Off Compulsory

Whether it fird or not is another story, but that is what it says in the EXIF. :lol:
Author:  cloaked_wolf [ Sun Mar 25, 2012 12:47 pm ]
Post subject:  Re: Wolfie's learning thread
Definitely didn't fire but interesting info. Maybe it was set to those modes automatically/default but I was able to override?
Author:  belchingmatt [ Sun Mar 25, 2012 12:57 pm ]
Post subject:  Re: Wolfie's learning thread
I get lost in the flash settings on my camera easily. The gf's camera gives out a little puff of smoke from the flash whenever it fires. :)
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