Macro focus frustration

[The Woodman]

I usually use a compact Nikon P5100 and struggle with certain types of shots.

For instance I was taking shots of cave spiders and their egg sacs yesterday from a range of 3-5cms. Out of 47 images, only 4 were in focus and those were the ones where I'd turned the camera upside down to get the lense closer to the roof of the cave!

Similarly when taking pics of small insects on grass, auto focussing is a problem.

Despite the subject being in the middle of the frame, the background is perfectly in focus, albeit a few mm further than the subject, and the subject is out of focus.

It's as if the rangefinder is not aligned with centre of frame Is it due to parrallax error or is there anything I can do to rectify the situation?

[slimrbp]

Looking at the camera specs the minimum focussing distance is 4cm at the wide angle zoom setting so it might be that your just a touch too close to the subject so the camera cannot focus on it?
As the camera has manual focus you might want to try a technique I use when doing 1:1 macro on my SLR. Manually set the focus so it as close as it can go and then move the camera towards the subject, taking the picture when it is in sharp focus, although I have to admit I don't know easy that would be on your camera.

[nightshade]

I know its old technology but you may have a focal plane mark somewhere on the camera body so you could measure your closest focus, I have used string from the tripod bush and even a wire focus fram made from an old lampshade.
Easy enough to check focus with a digital, I had to develop and print mine!

[Geoff F]

I suspect that the problem is likely to be the auto focus preferring to focus on a sharp edged target, like grass or twigs, instead of the soft bodied intended subject.

Manual focus always works best for me, although that also requires a tripod for best results.

Some species tend to move faster than I can manually focus so auto focus is the only answer; but my results are usually disappointing.

For instance, today I was attempting to photograph some garden birds which were flitting around faster than I could focus; so I switched to auto. I didn't get a single shot that I would consider to be properly focused even with a tripod.

[the naturelover]

My advice. follow richards technique. i always do this. use manual focus and move the camera to compose the picture. remember most cameras are not as intelegent as you think. they consider the whole frame when measureing exposure and focus in auto mode. unless you can force them to "centre spot"
If you have to use "auto" try bracketing as you would with exposure but move the camera slightly left righ up down until you find the position where the subject is in perfect focus.
As for cave subjects. As an ex caver with some 25 years of experience. who has rubbed shoulders with the worlds greatest cave photographers and never managed to take a half decent photograph underground.
remember you are in possible the worst enviroment for photography on earth.
Limestone sucks up light at least double the exposure and double the flash setting. As it is pitch black Use a small torch ie maglight to highlight the subject to focus. keep the camera in an "ammo" box for protection from bangs and moisture. Let the camera adjust to the enviroment for a short while to prevent fogging. And DO NOT breath out when taking a picture as your'e breath will cause the biggest fog you will ever see.
Hope this helps.
regards tn.

[The Woodman]

Thank you all for your comments. They are very useful and I will put them into practice in the next couple of days when I get a chance to get underground again.

I like the idea of the lampshade frame to get a steady and constant fix on the subject. Anything to prevent wobble whilst standing on one leg, camera on one hand at arms length and holding breath!

Thanks again and a Happy Christmas to you all.

[diggleken]

Just to add, if I understand the problem correctly (?) - I find that when the subject is tiny , the autofocus doesnt 'read or sense' it and so exposes for a more solid object, as has been said, which is the background you dont want.
Play with exposure more to understand whats happening and cheat the readings - or use manual.
You get used to it and it works.
Cheers
Ken

[The Woodman]

Your understanding is spot on, Ken.

I'm afraid I'm one of those people who rely on autofocus all the time but my New Years resolution is to investigate those other settings on the top knob.

99% of the time it is fine but on that odd occassion....

Doesn't exposure relate to the amount of time the lense is open rather than the focusable distance? You're talking to a novice here!

As a complete aside and with reference to your signature, I remember an interview between Bob Harris and the Captain in the early seventies on the Old Grey Whistle Test. Bob asked him a question and he replied, "Radiator" which flummoxed Bob completely, especially when he asked again and got the same answer. An impressionable time.

[diggleken]

Your absolutely right, but you knew what I meant! Old age................
Radiator!
Brilliant stuff - and good luck and merry christmas.

[ChrelizG]

Originally Posted by slimrbp

Looking at the camera specs the minimum focussing distance is 4cm at the wide angle zoom setting so it might be that your just a touch too close to the subject so the camera cannot focus on it?
As the camera has manual focus.....

Have only just joined/seen this thread. This is a Coolpix P5100? I bought mine basically for digiscoping, as it has a much bigger monitor than my earlier 4500. I assumed that it had manual focus, as the 4500 has, but can find no reference to it in the manual. Have I missed something?

Re: the original question - I use the spot AF & macro setting on one of the user-controlled modes, then it's a question of juggling to get the AF to lock onto what you want it to see. As others have said, light's important. The AF assist lamp is way off centre when in close, but might help (if it doesn't scare your subjects!). When the AF works, both compacts get excellent macro shots, though I still prefer the 4500!