Posted by Daniel Read on November 27, 2007 at 11:09 AM
I think this is a female common darter, Sympetrum striolatum. Taken this summer at Magor Marsh, nr Cardiff. I realise this is maybe lacking a bit of critical sharpness, but i was please with how the colours of the dragonfly and the background complemented each other.
Nikon D50
1/125/
f/4.5
ISO 800
Sigma 105 mm
Posted by Andy Astbury on November 27, 2007 at 11:16 AM
They are super dragons to photograph Daniel and I think this is pretty good
I'd struggle a bit with this 'cos I use the 180 Sig with shallower DoF - I'd have to do a 2 or 3 shot focus stack to get this much in focus at f4.5 so I wouldn't worry too much if I was you
You could maybe give this image one or two passes of USM set to 30, 0.3, 0 just to make it crispen up a bit, but it's nice
I'd struggle a bit with this 'cos I use the 180 Sig with shallower DoF - I'd have to do a 2 or 3 shot focus stack to get this much in focus at f4.5 so I wouldn't worry too much if I was you
Andy,
The depth of field will be virtually identical whether using a 105mm macro lens or a 180mm macro, or in fact a 50mm, or even a 600mm or a 16mm lens.
Unfortunately the image isn't displaying for me due to browser/internet problems that I'm having at the moment, but will try to re-visit when/if they get resolved.
Posted by Andy Astbury on November 27, 2007 at 12:07 PM
Justin - either you or I are speaking entirely different languages, or one of us is barking mad.
Subject distance = 10 feet
f number = f16
with a 55 mm lens your total DoF is 7.04 feet
with a 500mm lens it's 0.07 feet
FACT
The differences between 105 and 180 will be a lot smaller but they are there all the same.
Assuming the subject remains the same size (magnification) within the frame then the depth of field will be virtually identical no matter what the focal length.
I'll see if I can dig you out an article that will explain it much better than I could.
Apologies for the intrusion on your thread. I'll start a fresh topic to avoid intruding further, which will hopefully provide the answer.
Posted by Andy Astbury on November 27, 2007 at 1:30 PM
Hi Daniel - to be honest both myself and Justin are correct in what we've said, but we are talking about two different things.
In the most part we are always concerned with how close we can get to a subject - and there's invariably some limiting factor to our working distance, so we use a longer lens to give us more magnification.
The more you increase your focal length the less DoF you will obtain from a given f-number - as in the example I quoted before - though extreme, the example illustrates the point.
What Justin is talking about is this - different lenses yield different sized images of the same subject when the subject distance from the camera remains constant.
However, it is also possible to obtain images of the same size from different lenses by varying the subject distance from the camera.
When you photographed this dragon you were X feet away from it. If I had been with you, me being me, I would have stood in the same place you were, and with the 180mm I would have obtained a BIGGER image with LESS DoF using the same aperture from the same distance as you with your 105mm.
I could have taken the image from further away and ended up with an image the same size as you and the DoF would be the same as Justin hinted at.
For the most part though you should regard DoF for any given f-number DECREASES with INCREASED focal length.
Nice close-up, Daniel, although I do find the OOF wings in foreground a tad distracting.
What`s Magor Marsh like for photography? Come to think of it, where is it?! (I may be heading down Cardiff way tomorrow, although weather looks bad.)
Posted by Daniel Read on November 28, 2007 at 3:17 AM
Hi Jeremy,
Magor Marsh isn't bad, although it's fairly small, and you're limited by the fact that you have to stick to the boardwalks to get around. There is a bird hide, and a smallish lake, although in the summer the reeds grew up so high the view of the lake was obscured from the hide (i don't know what it is like now). I find it's great for insect life in the summer, absolutely teaming with dragonflies. And best of all, it's a very quiet nature reserve, i rarely see anyone else!
To find it, take Junction 23A off the M4. If you look on a map of Magor (try google maps), you can see a road running parallel to the south side of the railway line. The Marsh, and small car park are about half way along there.
Discussion
11 repliesNikon D50
1/125/
f/4.5
ISO 800
Sigma 105 mm
I'd struggle a bit with this 'cos I use the 180 Sig with shallower DoF - I'd have to do a 2 or 3 shot focus stack to get this much in focus at f4.5 so I wouldn't worry too much if I was you
You could maybe give this image one or two passes of USM set to 30, 0.3, 0 just to make it crispen up a bit, but it's nice
Andy,
The depth of field will be virtually identical whether using a 105mm macro lens or a 180mm macro, or in fact a 50mm, or even a 600mm or a 16mm lens.
Unfortunately the image isn't displaying for me due to browser/internet problems that I'm having at the moment, but will try to re-visit when/if they get resolved.
Subject distance = 10 feet
f number = f16
with a 55 mm lens your total DoF is 7.04 feet
with a 500mm lens it's 0.07 feet
FACT
The differences between 105 and 180 will be a lot smaller but they are there all the same.
Get a DoF calculator if you don't believe me
Assuming the subject remains the same size (magnification) within the frame then the depth of field will be virtually identical no matter what the focal length.
I'll see if I can dig you out an article that will explain it much better than I could.
Phil
Cheers,
Dan.
Apologies for the intrusion on your thread. I'll start a fresh topic to avoid intruding further, which will hopefully provide the answer.
In the most part we are always concerned with how close we can get to a subject - and there's invariably some limiting factor to our working distance, so we use a longer lens to give us more magnification.
The more you increase your focal length the less DoF you will obtain from a given f-number - as in the example I quoted before - though extreme, the example illustrates the point.
What Justin is talking about is this - different lenses yield different sized images of the same subject when the subject distance from the camera remains constant.
However, it is also possible to obtain images of the same size from different lenses by varying the subject distance from the camera.
When you photographed this dragon you were X feet away from it. If I had been with you, me being me, I would have stood in the same place you were, and with the 180mm I would have obtained a BIGGER image with LESS DoF using the same aperture from the same distance as you with your 105mm.
I could have taken the image from further away and ended up with an image the same size as you and the DoF would be the same as Justin hinted at.
For the most part though you should regard DoF for any given f-number DECREASES with INCREASED focal length.
What`s Magor Marsh like for photography? Come to think of it, where is it?! (I may be heading down Cardiff way tomorrow, although weather looks bad.)
Magor Marsh isn't bad, although it's fairly small, and you're limited by the fact that you have to stick to the boardwalks to get around. There is a bird hide, and a smallish lake, although in the summer the reeds grew up so high the view of the lake was obscured from the hide (i don't know what it is like now). I find it's great for insect life in the summer, absolutely teaming with dragonflies. And best of all, it's a very quiet nature reserve, i rarely see anyone else!
To find it, take Junction 23A off the M4. If you look on a map of Magor (try google maps), you can see a road running parallel to the south side of the railway line. The Marsh, and small car park are about half way along there.
Cheers,
Dan.