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View Full Version : HELP! I am trying to do a Stepped Greyscale test


joanns
19th December 2009, 02:31 PM
Hi, My name is Jo and I have just joined this site
I am in the process of doing an on-line photography course (I am a complete novice) and I have to do a Stepped Greyscale Test with a grey card to determine the dynamic range of my camera.

I appologise now for the log winded thread but this is what I have got to do - Outside open shade and at least half hour of constant lighting, I've set ISO 100 and f/8 on manual exposure, auto white balance and tried to manually focus on the card, Selected RAW format all as instructed- ok so far. (This where I am stuck) Now Ive got to take a meter reading off the greycard and in manual mode set shutter speed to get correct exposure without exposure compensation leaving aperture at f/8, write down this setting. Once I have got that sussed I have to do 6 exposures increasing shutter speeds by one stop intervals then returning to original setting and then decreasing shutter speeds etc.
I have the info screen up and have the EV value at the midway point (optimum exposure as described in the manual ?) The numbers I am writing down I presume is shutter speed (1/13 in this case) and the aperture value which as stated f/8 is that right ???? If that is all right then why can't I take the shot - I 'm pressing the button but nothing is happening the AF confirmation mark keeps blinking.
Please can someone help, I don't understand what I am doing wrong ?

Thanks in advance

EH1
19th December 2009, 03:13 PM
Sounds like you have`nt set the camera to manual focus (MF) & the camera is telling you that the auto-focus (AF) cannot lock onto anything (as it is just looking at a grey card!) I hope this helps....................if not don`t be afraid to ask again ;)

BTW. Welcome to the forum! :)

peak4
19th December 2009, 03:18 PM
Hello and welcome to a friendly and helpful user group. :)
Don't get disheartened, I don't think you are doing anything wrong.
I'm assuming you are following all the required instructions, and the only problem is that the shutter isn't firing.

As you rightly say, the AF light is blinking. That's because the camera needs an area of contrast to focus on, and with a plain grey card, it clearly doesn't have one.

You can set the camera to take a photo, only when the subject is in focus, or you can set it to release the shutter regardless.

The normal defaults are the former for single auto-focus and the latter for continuous auto-focus.
It's called release priority and can be found in the menu at
"Spanner 1 Release Priority S" it's default is "Off"
Swap it to "On" and now have another go.

Just remember to set it back afterwards or you will wonder why you get lots of out of focus shots.:confused:

It's not covered in the basic paper manual of the E-500, so you need to have a squint at the .pdf advanced manual.

The manual does not seem to be available from Olympus UK, but is available HERE FROM OLYMPUS USA (http://www.olympusamerica.com/files/EVOLT_E-500_Advanced_Manual_EN.pdf)

Head for Page 75, but beware it's a 15 Meg download if you are on a Dialup connection.

Do stay around, and Seasons Greetings *chr

P.S. I really should drink more coffee. EH1's reasoning is faultless.
A much quicker solution than mine, is to hit "Right Arrow/East" labelled "AF" on the thumb buttons and set AF to Manual. *zzz

photo_owl
19th December 2009, 03:25 PM
Whilst this is fine in principle I think it's much easier to just make sure the camera is in MF mode in this instance, as Edward suggests...

peak4
19th December 2009, 03:33 PM
Whilst this is fine in principle I think it's much easier to just make sure the camera is in MF mode in this instance, as Edward suggests...

Yow are of course correct I added the postscript whilst you were typing your reply. :D

joanns
19th December 2009, 06:22 PM
HI Thanks everyone for your input, your right I hadn't changed auto focus to MF (Thought it would be something silly !!!!), Will have another go tommorow, weather depending of course.....
Will definately download that manual Bill Thanks.
Hopefully it will all go according to plan or I will be back asking for your help again.

peak4
19th December 2009, 06:30 PM
Pleased to help, but next time I'll try engaging brain before typing. :o

EH1
19th December 2009, 06:32 PM
Hopefully it will all go according to plan or I will be back asking for your help again.


Don`t be afraid to ask for any other help.........................sounds like your on a SPI course?

joanns
19th December 2009, 06:50 PM
Hi Edward
I'm doing a course by the "Photography Institute" - The Professional Photography Course by George Seper
I'm really enjoying it but finding it quite tough as I think its aimed at people with quite a bit more "basic" knowledge than me - but hey it's making me try harder and finding these things out are certainly making me understand my camera and it's functions alot better, I'm only on Module 3 of 12 but have so far got 90% on both modules 1 and 2.
Have you had any dealings/heard anything about the course ??? Have I picked a good one? It certainly seems quite in depth !!

EH1
19th December 2009, 07:42 PM
Hi Edward
I'm doing a course by the "Photography Institute" - The Professional Photography Course by George Seper
I'm really enjoying it but finding it quite tough as I think its aimed at people with quite a bit more "basic" knowledge than me - but hey it's making me try harder and finding these things out are certainly making me understand my camera and it's functions alot better, I'm only on Module 3 of 12 but have so far got 90% on both modules 1 and 2.
Have you had any dealings/heard anything about the course ??? Have I picked a good one? It certainly seems quite in depth !!


I have heard good things about it from other people in the past, but no it`s not a course I have done myself. I hope you continue to enjoy it :)

joanns
4th January 2010, 10:58 AM
Hi Happy New Year to everyone, back again - more help required please to understand my results this time ! I finally managed this test after having to wait for the right weather and then having to play about with the custom WB. results are as follows :-

Zone R G B

0 0 0 0
1 9 9 9
2 17 17 17
3 34 34 34
4 63 63 63
5 107 107 107
6 167 165 166
7 223 222 222
8 255 255 255


I now I understand I have a dynamic range of 9 f/stops from black to white,
My grey card exposure is zone 5. Because I only have have 2 stops below my meter reading does this mean my camera favours the highlights or shadows ?
How do I know from these results if my camera suffer colour shifts at the exposure extremes ? (Is it if the numbers accross the RGB are not the same i.e zone 7 - I have a colour shift slightly on red ?? )
Also I have to say about overexpose and underexpose i.e if I underexpose a highlight by three stops I will still retain detail and if I underexpose a shadow by three stops I will retain detail ? This bit I cannot seem to undertand.

I hope someone can help, as I said before the course work doesn't explain it very well (or I'm just stupid !!) and I have been trying so hard to get my head round it on my own but now need your help please.

photo_owl
4th January 2010, 11:57 AM
Hi Happy New Year to everyone, back again - more help required please to understand my results this time ! I finally managed this test after having to wait for the right weather and then having to play about with the custom WB. results are as follows :-

Zone R G B

0 0 0 0
1 9 9 9
2 17 17 17
3 34 34 34
4 63 63 63
5 107 107 107
6 167 165 166
7 223 222 222
8 255 255 255


I now I understand I have a dynamic range of 9 f/stops from black to white,
My grey card exposure is zone 5. Because I only have have 2 stops below my meter reading does this mean my camera favours the highlights or shadows ?
How do I know from these results if my camera suffer colour shifts at the exposure extremes ? (Is it if the numbers accross the RGB are not the same i.e zone 7 - I have a colour shift slightly on red ?? )
Also I have to say about overexpose and underexpose i.e if I underexpose a highlight by three stops I will still retain detail and if I underexpose a shadow by three stops I will retain detail ? This bit I cannot seem to undertand.

I hope someone can help, as I said before the course work doesn't explain it very well (or I'm just stupid !!) and I have been trying so hard to get my head round it on my own but now need your help please.

not sure where you get 9 from - on that data I would say it's between 7 and 8 (you don't necessarily have full stops between 0 and 9 or 222 and 255). if mid grey is at 5 you have more lattitude below than above so it's favouring the shadows. for digital this is appropriate because there is more data per bit in the highlights and little by the time you get into the shadow areas and, importantly, the camera will change the exposure in ESP and area exposure programs if it detects significant highlights that would be blown. This is where it's important in practice to understand what the computer is doing (unless you are using spot metering and doing it all yourself as this 'lesson' is teaching)

yes re colour shif although on those numbers I would suggest that you don't have a colour shift at all - if you re-sample a few times and get exactly the same differences at 6 and 7 then fine (but I suspect you wouldn't)

regarding exposure, you know that if you meter an area it will give you exposure for 5. therefore you can work out from that what would happen to any other source (than mid grey) what would happen if you simply metered and exposed it. best way to look at it is that if you went to +3EV when shooting the card it will be white/no detail, -5EV and it's black/no detail - everything else is a translation from that.

if I have goofed in the above I am sure some kind soul will advise!

joanns
4th January 2010, 12:09 PM
I got 9 because on the lesson my tutor put his results on and they went from zone 0 to zone 9 being 255 and he said his was 10 stops dynamic range ???

photo_owl
4th January 2010, 12:31 PM
0 is black
255 is white

they all go from one to the other but the key is in how many steps/stops.

in the results you have posted your camera does it in between 7 and 8 steps...

joanns
13th January 2010, 11:50 AM
Hi all, Just a quick update I have just got results back and I got 10/10 on this module, Thanks to all for your input and helping me understand it better. Here's to module 5 on Histograms .......