Fuji F30 Exposure Questions (1 Viewer)

NoSpringChicken · Jul 3, 2007

I recently bought a Nikon ED50 scope with a 13-40 zoom lens to use with my Fuji F30 for digiscoping. The first results were very promising but I took it out on Sunday on a nice, bright day and only achieved a couple of shots which weren't a complete disaster.

The scope zoom was at its widest setting and I had the camera in Aperture Priority mode with the aperture also at its widest. The ISO was set to 200 or 400 but most of the photos were taken at f/5.0 with a shutter speed of 1/80 -1/180 second. This meant that most of them were blurred and, strangely, were underexposed too

I was also having problems with the autofocusing. I was focusing the scope by eye first, then swinging the camera into position and half pressing the shutter button to focus the camera. Much of the time the camera wouldn't focus, however, and red AF warning appeared. Moving the camera and scope to select different parts of the image made no difference. On the other hand another subject would focus straight away with no problems. I had the camera set to 'Macro' mode with the focus assist switched off.

I am beginning to think that the 50mm scope and zoom lens are not really bright enough to allow fast shutter speeds at lower ISO settings and this is also upsetting the camera autofocusing.

Sorry for the wordy post but any theories?

Ron

kittykat23uk · Jul 3, 2007

Not much help I'm afraid but I have also been noticing the same thing (focus hunting) with my F31, even when the bird fills the scope and seems to be focused fine through the LCD screen. My exposures have generally come out either well-exposed or slightly overexposed. I have it set to -1/3rd ev usually and if it is still over exposed, I drop it by another 1/3.

NoSpringChicken · Jul 3, 2007

kittykat23uk said:
Not much help I'm afraid but I have also been noticing the same thing (focus hunting) with my F31, even when the bird fills the scope and seems to be focused fine through the LCD screen. My exposures have generally come out either well-exposed or slightly overexposed. I have it set to -1/3rd ev usually and if it is still over exposed, I drop it by another 1/3.

The strange thing is, it hadn't been a problem until Sunday and I hadn't noticed it all with my other scope. One other possibility is that I have to have the eyecup on the scope fully retracted to allow the camera to swing away, so there is a bit of gap between the camera lens and the eyepiece. I suppose light may be getting in and causing reflections on the eyepiece which confuse the autofocus. Is that possible?

You seem to be getting some very good results with your set up, Jo.:t: What adaptor are you using? I looked at all the used scopes at Cley Spy the day before you bought your Kowa but must have overlooked yours, probably as I was looking for an angled scope. I tried out a Kowa TSN601 (non ED) but, to be honest, I wasn't very impressed. I think the ED glass makes a big difference.

Ron

NoSpringChicken · Jul 3, 2007

Another question, Jo, if I may. What sort of ISO settings have you been using and roughly what shutter speeds do you end up with?

Ron

kittykat23uk · Jul 3, 2007

Hi Ron,

thanks so much for the compliments. I've tried to use as low an ISO as possible but as we've had such a lot of rain recently I've been using quite a variety to be honest.

Let's see:

The wood pigeon, sparrow pair, greenfinch, adult goldfinch, robin on the metal post, are all taken at ISO 200 shutter speeds, 1/450 f5.0, 1/80 f6.4, 1/58 f6.4, 1/75 f6.4, 1/56 f6.4, respectively,

The juvenile goldfinch, juvenile blackbird ISO 400, 1/150 F6.4, 1/90 F6.4,

The pair of collard doves, ISO 100, 1/240, f5.0

The robin on the branch of the buddleia bush ISO 800 1/56 F5.0.

If you go to my flickr account you can see all of the exif data by clicking on the image and then selecting more properties from the Additional information menu on the right hand side of the picture.

http://www.flickr.com/photos/8773601@N03/633073780/in/set-72157600503537448/

http://www.flickr.com/photo_exif.gne?id=633073780&context=set-72157600503537448

As for the adapter I use the Baader microstage adapter for my garden shots. My three newest shots were all hand held though:

http://www.birdforum.net/gallery/showphoto.php/photo/148294/limit/recent

ETA: as far as the whole Kowa ED vs Non ED, I was able to try out the 614 (ED) against the 611 (non ED) and it was really quite noticeable, especially if you would be considering a zoom eyepiece. I tried out the new TSN zoom and there was a large amount of colour distortion on the non ED scope but it seemed to work fine on the 614. If you do go for a Kowa, don't get the new TSN 20x wide eyepiece, it is too wide to be usable with our cameras! I got an older 20x and that fits really snugly with the fuji's lens with the eyecup folded up. I think the new zoom would also work fine though.

NoSpringChicken · Jul 3, 2007

Hi Jo,

Thanks for the info. Looking at the shutter speeds, quite a few are relatively slow (i.e. less than 1/100 sec). It seems that, if I want to photograph birds which aren't completely still, I will need to bump up the ISO a bit and not worry too much about the extra noise. I thought I would be able to get away with 100 or 200 ISO but that may not be possible.

With the autofocus problem, I'm wondering if I managed to switch off the Macro mode when I was setting the 2 second timer on some shots. It's quite easy to do that if your finger is in slightly the wrong place on the arrow button.

Back to the drawing board. Still it wouidn't be fun if it was easy, would it?

Ron

NoSpringChicken · Jul 3, 2007

kittykat23uk said:
ETA: as far as the whole Kowa ED vs Non ED, I was able to try out the 614 (ED) against the 611 (non ED) and it was really quite noticeable, especially if you would be considering a zoom eyepiece. I tried out the new TSN zoom and there was a large amount of colour distortion on the non ED scope but it seemed to work fine on the 614. If you do go for a Kowa, don't get the new TSN 20x wide eyepiece, it is too wide to be usable with our cameras! I got an older 20x and that fits really snugly with the fuji's lens with the eyecup folded up. I think the new zoom would also work fine though.

I tried out the Kowa TSN 601 with a zoom lens (I don't know what type) against the Nikon ED50 with the MC 13-40 zoom and at the widest setting there wasn't too much difference. As soon as I zoomed in on a pigeon on a pale, muddy path, however, everything turned purple on the Kowa whereas there wasn't any noticeable CA on the Nikon. That decided it for me and I bought the ED50. A new TSN 603 was outside my budget.

I love the Nikon as a scope and if I can sort out the digiscoping problems I will be extremely happy. Nikon recommend their DS range of lenses for digiscoping but according to their sales information the MC zoom should work all right but with a bit more vignetting.

Ron

Feathered one · Jul 3, 2007

Ron
You wrote "With the autofocus problem, I'm wondering if I managed to switch off the Macro mode when I was setting the 2 second timer on some shots. It's quite easy to do that if your finger is in slightly the wrong place on the arrow button."

Dont forget you can always check if you had the macro on or off by looking at the Exif information on your pictures.
Personally I use the F30 with macro off. I did lots of tests on a static target and reckon off was best.
Light shining between the F30 lens and the scope eyepiece can upset the camera, at worst you can have light spots/crescents on the picture you have taken.
The DS fixed eyepieces will let more light through than a zoom, and will have more eye relief. have a look at the table on Nikons website.

Keep trying, don't give up, you will get good results.

Malc

Neil · Jul 4, 2007

Ron,
You will suffer with lower light levels through a 50 mm scope. Some tricks to help -
1. with a black marker pen blacken the silver front of the lens (making sure not to get any on the glass lens ). This will help prevent light bouncing around the lens area and improve contrast.
2. the AF may be having trouble with focus on moving subjects (eg birds at feeders ) . Try focusing on the birds feet or perch. You should also get more contrast here. Use Center AF.
3. Bump up the iso to 800 , or whatever it takes to get at least 1/500 th shutter speed
4. When you get focus in the scope try "tweaking" the focus a little beyond this point and seeing if the camera will focus.

I hope this helps, Neil.

NoSpringChicken · Jul 4, 2007

Feathered one said:
The DS fixed eyepieces will let more light through than a zoom, and will have more eye relief.

Does anyone know how the eye relief of an eyepiece relates to the camera in practical terms? For example the lens on my scope has an eye relief figure of 14.1mm at the widest setting. Does this mean that some part of the camera lens needs to be approximately 14mm from eyepiece? If so which part – the front of the lens, the diaphragm or the plane behind the lens where the image focuses? If the latter is the case, approximately how far behind the front of the lens would that be?

Also I have never had a definititive answer as to how far from the eyepiece to set the camera. I normally switch the camera on and move it backwards or forwards until the vignette is sharp. In fact I normally move it as far back as possible while maintaining the sharp vignette. Is this correct or is there a better way to do it?

Ron

Neil · Jul 4, 2007

Ron,
" Vignetting is the effect caused when the entire frame of the image is not illuminated, leaving a circular image with surrounding black. It occurs when either the objective lens of the camera is larger than the exit pupil of the scope, or when the curvature or mounting of the objective lens of the camera is farther away from the eyepiece of the scope than the scope's eye relief. For this reason, most digiscopers prefer cameras with small objectives, which can be brought very close to the scope's eyepiece. In general, pocket-sized digital cameras with large zoom ranges are also problematic, as their zooming lens elements recede from the eyepiece when zooming to larger magnifications." quote from http://www.optics4birding.com/digiscoping.aspx

Slide the camera backwards and forwards until the vignetting circle is sharp and at it's largest. The Fuji is one of the best cameras for the shorter eye relief eyepieces so should not have to be moved again. My A640 and 8400's position needs to be adjusted at various camera zoom positions to keep vigneting out. Neil.

NoSpringChicken · Jul 5, 2007

Thanks for that Neil. I spent some time last night experimenting with the position of the camera and, in fact, there is a fairly limited range where the vignette is clearly defined. In front of, or behind, this position the image rapidly disintegrates. I chose the position where the image looked brightest with a clean outline to the vignette.

I also adjusted the adapter to ensure that the camera lens was absolutely square to the scope eyepiece (I noticed that it was pointing slighty upwards before). The outcome of all this is that the vignette now clears completely just before the midway position on the camera zoom. This in turn means that slightly wider aperture settings of about f/4 are now available which should allow for slightly faster shutter speeds.

I was going to try some trial shots in the garden but it started raining again and every bird in the area promptly disappeared for the night.

Ron

kittykat23uk · Jul 5, 2007

Hi Ron,

do you put food out for the birds? I have found that they will still come to the feeders when it rains. More so, than when it is sunny!

NoSpringChicken · Jul 5, 2007

kittykat23uk said:
Hi Ron,

do you put food out for the birds? I have found that they will still come to the feeders when it rains. More so, than when it is sunny!

I don't have any feeders, fat balls or similar attractions. My back lawn is a bit of a state at the moment so there is normally a selection of sparrows and greenfinches after the seeds there.

There were a couple of blackbirds flying about with their beaks full of worms but they wouldn't stay still long enough for me to photograph them and as it was starting to get dark I gave up and went indoors to photograph the 'domestic owl' instead (photo attached.) This was in another room, about 20 ft away and was shot in incandescent light at ISO800, so the background is a bit noisy.

Ron

kittykat23uk · Jul 5, 2007

aaahh, sweet.

NoSpringChicken · Jul 5, 2007

kittykat23uk said:
aaahh, sweet.

You should see him in his regular occupation as a door stop. He's a tough little blighter.

Ron

NoSpringChicken · Jul 9, 2007

After experimenting at home I decided that the camera worked best with Macro turned off but I went to Minsmere yesterday and had the same problem. Sometimes the camera focused straight away but another time it wouldn't focus at all, despite moving the focusing target all over the bird – head, legs and eyes

Eventually, after I had an Oyster Catcher posing beautifully and filling the frame in the sunshine and I wasn't able to get the camera to focus, I gave up as there was a very real danger that the scope and camera might have ended up being hurled out of the hide in frustration.

Just before we went home I had another go and encountered the same problem. I then switched on Macro and the camera immediately focused. Go figure! Unfortunately, I don't know if that was a fluke or not until I have another chance to try.

In the meantime here are two of the better shots I have taken. They're not brilliant but if they could all be like this I would be quite satisfied.

Ron

Newton Stringer · Jul 10, 2007

Hiya Ron

Yep I have recently bought an F31 and sometimes it refuses to focus like that.... Mines just held onto my eyepiece with a simple collar I made... I've found that quickly removing it from the scope, focussing on something else and then putting it back on to start focussing again often solves this problem... not ideal but it seems to work most of the time...

NoSpringChicken · Jul 10, 2007

newton birder said:
Hiya Ron

Yep I have recently bought an F31 and sometimes it refuses to focus like that.... Mines just held onto my eyepiece with a simple collar I made... I've found that quickly removing it from the scope, focussing on something else and then putting it back on to start focussing again often solves this problem... not ideal but it seems to work most of the time...

I think there is something in what you say there. When the camera is swung away and before I swing it back again I might try half pressing the shutter to get it ready for refocusing.

I tried some more shots in the garden last night and, using the Macro mode, the focusing worked straight away about 90% of the time. I'm now getting a very comprehensive collection of photos of sparrows eating bread.|

|

Ron

stanacko · Jul 10, 2007

Hi,
I use the f11 and if I have it too far zoomed out it wo,nt focus.
Stan.

Fuji F30 Exposure Questions (1 Viewer)

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