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View Full Version : HELP! Dummy guide to understanding image flaws?


RobEW
26th February 2017, 06:56 PM
Hi. Newcomer question here. Newcomer to "proper" (not point-and-click) digital photography that is.

I'm still trying to work out why some of my images (with E-M5 or E-M1 and various lenses) come out quite well, and others with far less detail. I peer into them at high magnification on the Olympus Viewer software and some have crystal clear detail, others less so.

Is there some book or website which can show me how to look at an image and understand which of various possible causes has limited the quality of my image? I can think of several possible causes:

- too high ISO
- movement of subject or camera
- not well focussed (or that part of the image not well focussed due to low DoF)
- limitation of the lens itself
- quality of the lighting on the subject

and maybe other possible causes.

Is there an easy "idiots' guide" to understanding what's wrong with an image and how to do better next time?

pdk42
26th February 2017, 07:03 PM
Well young Anakin...

There are so many ways to make a bad photograph IMHO and the list includes all the ones you listed plus a good few more. The best thing is to post some examples and get some feedback. Many of the members on here have a lot of experience, including those who are judges and members of professional bodies and such like. You'll get great advice just by asking, I'm sure.

As to an idiot's guide - I think that Cambridge in Colour is a good place - if you're technically minded:

http://www.cambridgeincolour.com/

RobEW
26th February 2017, 07:10 PM
Thanks pdk42. I'll try C in C.

Not sure I want to parade my faults in front of the world. Maybe I should have adopted a more anonymous nickname on here. :-)

pdk42
26th February 2017, 07:19 PM
Not sure I want to parade my faults in front of the world. Maybe I should have adopted a more anonymous nickname on here. :-)

I wouldn't worry about that. It's probably the fastest way to learn since advice will be personal and directly-linked to whatever issue you face. Don't be shy!

Nawty
26th February 2017, 09:35 PM
As a generalisation I would say nine times out of ten it is due to poor light.

Poor light leads to flat images, high ISO, slow shutter speed, wide apertures and missed focus.

Photography is about light, understand that and you're well on the way.

Naughty Nigel
26th February 2017, 09:50 PM
As a generalisation I would say nine times out of ten it is due to poor light.

Poor light leads to flat images, high ISO, slow shutter speed, wide apertures and missed focus.

Photography is about light, understand that and you're well on the way.

This is correct. Good light makes it much easier to take good photographs.

The first objective is to get the exposure somewhere about right, so it isn't too light with burnt out highlights, or too dark with lots of black shadows. That should be easy enough with the EM5 set in any of the automatic modes, as it has a good metering system.

When you examine your images, have a good look to see what how the main point of interest looks.

If the image is 'fuzzy' it is probably out of focus. You might also find that the point of focus in not where you wanted it! Manual focusing might help but make sure you have the eyepiece dioptre adjustment set correctly first. (The little knob beside the viewfinder lens.) Closing down the lens aperture to (say) f5.6 or f8.0 will also help focusing.

However, if you can see 'movement' in the image (often as small circles or up and down movements) you probably have camera shake, caused by too long an exposure.

The image data should help you to analyse your shots.

RobEW
27th February 2017, 07:35 PM
Yes, I do think poorer light might explain the differences in quality between two different days photographing very similar shots in the same location. The first day had tremendous light; the second mediocre.

I think on the dimmer day I was tending to keep my aperture open wide and compromise on ISO and/or shutter speed. Getting to know which compromises have the lower negative impact on IQ is part of a learning process I guess.

As my previous experience of "proper" photography was about 20 years ago on Olympus OM2N (35mm film camera) I'm used to manual focussing, and think the new facilities to magnify the viewfinder image and provide peaking during MF are wonderful.

(Other "new" facilities afforded by digital photography of course include stabilisation, varying ISO per shot instead of per reel of film, autofocus and all its clever variations, instant feedback on the image via the screen, and of course the near zero incremental cost of taking extra shots.)

Naughty Nigel
27th February 2017, 08:13 PM
Olympus' Image Stabilisation system is good, if switched on, and should allow hand-held shots at 1/30 second or above if you have a steady hand when using focal lengths of 40 mm or less.

It is possible to go slower, (I have managed 1/8 second hand-held on occasions), but you need to brace yourself, take a deep breath, and keep very, very still!

It sounds as if you have got the hang of the focusing system, so shutter speed and camera shake are more likely to be the problem. I presume that the lens and sensor are all clean?

I have found that image quality from the EM5 is not massively affected by ISO speed settings, within reason. I usually try to keep between ISO 100 ('Low) and ISO 400 whenever I can, to keep images as clean as possible. Once you go beyond ISO 800 you can expect some noise, but it is not usually objectionable until you go to ISO 1,600 and beyond.

I usually set my ISO to 'automatic', but have limited the auto range to ISO 100 - 1,600. This can be overridden manually if required.

Can I suggest that you take some photographs in good light to make sure everything is working properly, and so that you know what to expect. You can then compare your results in lower light to see what, if anything, is going wrong.

RobEW
27th February 2017, 09:16 PM
Hmmm. I was hand holding (whenever possible supported by a nearby wall or fence) sometimes at slower shutter speeds and longer focal lengths than that.

I tend to use aperture priority a lot with ISO floating but less limited than yours (6400 max). Maybe that's way too high. Advice seems to vary. In the old film days 100 "ASA" (old word for ISO) was standard and 400 a bit "out there".

As you suggest, I'll get out in excellent light and do some more specific experimenting.

P.S. I like the profile photo. Are you an organist?

Zuiko
27th February 2017, 09:41 PM
P.S. I like the profile photo. Are you an organist?

Sometimes, during various debates on this forum, Nigel has been known to pull out all the stops! :D

pdk42
27th February 2017, 09:45 PM
Sometimes, during various debates on this forum, Nigel has been known to pull out all the stops! :D

I thought it was a mixture control on an aeroplane!