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Subject: Digiscoping with Ricoh GXR equipped with its 24-72mm lens [Print This Page]

Author: lwingkay Time: 21/02/2010 20:57 Subject: Digiscoping with Ricoh GXR equipped with its 24-72mm lens

A picture taken with GXR and 24-72mm Lens

Bought a Ricoh GXR body and its interchangeable 24-72mm zoom lens lately and tested them out yesterday on my Swarovski's fieldscope incorporated with a 30x-eyepiece. Here is a shot taken:

As the weather becomes warmer, I do hope that I can get more familiar with the settings in the GXR and can post more pictures for reference purposes.

Re: Vignetting

I used my own adaptor to link up the Swarovski eyepiece with the Ricoh zoom lens. If you are using the DCA by Swarovski, the following data will not work on your pictures.

The focal length stayed at 7.3mm (i.e. 35mm in 135mm format) in the above shot. If I shoot in portrait format (i.e. in vertical format as the one above), vignetting will disappear between 32mm (should be 34mm) and 62/65mm and from 62/65mm onward to 72mm, slight vignetting will reappear on the upper part of the frame. Though so, the intensity of vignet is pretty light.

With the 45x-eyepiece, the vignet totally disappears from around 30mm onward.

Feel free to visit the vignet-testing pictures at the following link: http://www.flickr.com/photos/wk7leung/sets/72157623378540406/ There, the focal length used in each picture has been included.

Pete

[ Last edited by lwingkay at 21/02/2010 21:15 ]

Author: puppymic Time: 23/02/2010 00:34

好似唔錯喎， Thanks

Author: lwingkay Time: 23/02/2010 17:20

Quote:

Original posted by puppymic at 23/02/2010 00:34
好似唔錯喎， Thanks

Will experiment with the new camera in the coming weekend ... do hope that it turns out to be another Nikon CP8400, which, in my opinion, is irreplaceable as far as digiscoping is concerned.

My first impression with the GXR is that it is practically impossible for the camera to be used on the Swarovski fieldscope using the DCA as the linking adaptor because of the following reasons:
a. the GXR adaptal tube accepts a 43mm adaptal plate for the opening that connects with the DCA and there is no such a plate provided in the DCA set.
b. the anterior end of the zoom lens of the GXR is about 4mm from the very end of its adaptal tube and this makes it difficult for the zoom lens to get as close as possible to the eyepiece of the fieldscope. The result is vignetting.
c. the vignetting condition in (b) above becomes even more complicated taking into account the fixed height of the DCA. You just cannot reduce the height of the DCA with a view to bringing the eyepiece closer to the zoom lens.

To resolve the problem, you have to use a DCB. In my case, I have made a retractable adaptor to cope with the situation.

Hope that this weekend, the weather is just right for field work. If situations permit, I will then post some more shots up here for viewing.

Pete

[ Last edited by lwingkay at 23/02/2010 22:17 ]

Author: lwingkay Time: 25/02/2010 19:22

Taken with a 30x-eyepiece (should be a 45x) and Ricoh GXR 24-72mm

[ Last edited by lwingkay at 25/02/2010 22:58 ]

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Author: lwingkay Time: 27/02/2010 21:14

Shooting particulars

Taken with the 30x and 45x eyepieces, Ricoh GXR and its 24-72mm zoom lens
Tai Shui Hang
Feb 27, 2009 pm

3 Common Kingfisher (45x-eyepiece with the zoom lens focal length at 15.3mm, i.e. 72mm for the 135mm format)

4 Oriental Magpie Robin (45x-eyepiece with the zoom length focal length set at 6mm, i.e. 28mm for ther 135mm format)

5 Red-whiskered Bulbul (45x-eyepiece with the focal length set at 15.3mm, i.e. 72mm for the 135mm format)

6 Chinese Bulbul (30x-eyepiece with the focal length set at 15.3mm, i.e. 72mm for the 135mm format).
Vignetting occurred and the vignet set in from about 65mm onward)

Lens quality

From the digiscoping point of view, this 24-72mm zoom lens is just fair in quality. Since I have been using Nikon CP8400 and P5100 for digiscoping, my comparison was made based on these two lenses.

On the whole, CP8400 is the best and this 24-72mm is the worst. The 24-72mm is not a sharp lens all the way through. Its sharpness is satisfactory only for the range from 32mm to 50mm. At the tele-end, the image produced is not solid enough, with details in the shadow difficult to be disnerned.

Color modes and quality

The images above were all taken in the natural color mode. If the vivid mode or the standard mode had been used, the details in the shadow positions would have become dull and messy. The colors of the images would have been quite artificial as well, with the tone falling toward the blue and green sides.

GXR's EVF and exposure

The image of the hot-shoe-mounted EVF is bright and vivid and it gives you the impression that the shot is well taken as regards focusing and exposure. However, when the images are viewed on the computer, they turn out to be darker. I don't know why this has been the case. This fallacy is exposure is detrimental for you have been at home seeing all the mess.

The image on the EVF is contrastive as well, so despite the fact that the exposure is normal, the details in the shadow tend to be pretty dark-out, so I tend to increase exposure to have the details in the shadow to be revitalizable in post treatment.

I shoot with the centre-weight average metering mode all the time when doing digiscoping. For the GXR, I usually have to increase exposure by 2/3 a stop to 1 stop in order to obtain the kind of exposure I normally could get while working with the Nikon cameras. I don't know the reason why. Probably, the white letters on the circumference of the zoom lens may have been the cause. These letters reflect light back onto the eyepiece, complicating exposure.

Raw and JPEG images

It is normal that the JPEG images are better looking than the raw ones. This works on GXR. Strangely, the JPEG files tend to be less contrastive than the raw ones. The complication to me for that is that it is less feasible to monitor the color and tone of the raw image since it has already been contrastive.

Image processing software

I use Photoshop CS4 and I don't know if it works well for Ricoh's DNG raw images. My experience is that while in CS4, there seems to be not much space in Ricoh's raw images for CS4 to manuver as regards exposure, tone and colors as the images have been pretty contrastive by themselves.

Focusing

Fast and accurate on the whole.

Overall experience

Experimenting with the camera for an afternoon, I have the feeling that GXR is not that suitable for digiscoping purposes. Probably, this has been so because GXR's color management philosophy is more for the creation of vivid images that appeal to the senses. It depends on the quality of the primary light to make the color philosophy works. So when processing secondary images from the eyepiece, the GXR fails to yield the kind of vividity that its digit processing unit is engineered to produce.

In the mean time, if you would like to see more details in your bird shots, GXR may as well fail you. Vivid images tend to be contrastive in tone and so, it is natural that details in the shadow positions of GXR's shots will become less discernable. In addition to this, frankly speaking, the 24-72mm is not an outstanding lens!

Pete

[ Last edited by lwingkay at 27/02/2010 23:22 ]

Author: lwingkay Time: 28/02/2010 09:33

JPEG and DNG raw files for comparison

7 Images from Nikon P5100

a. The original JPEG original file of a Plumbeous Redstart

b. The JPEG above that has been retouched.

8 Images from Ricoh GXR taken with its 24-72mm lens

a The raw DNG file of the shot posted in the previous thread [More contrastive than the JPEG file]

b The JPEG file without retouching that came along with the DNG file

c The retouched DNG file in which contrast has been a bit tuned. This shot is the same as the one posted in the previous thread.

9 Images from Nikon CP8400

a An original JPEG file of a common kingfisher taken with a 45x-eyepiece

b The retouched JPEG file of the above shot

[ Last edited by lwingkay at 28/02/2010 09:47 ]

Author: puppymic Time: 28/02/2010 10:21

可能唔識用，我發揮唔到 CP8400 既威力，而且唔係幾忍到佢咁慢既儲相時間

Author: lwingkay Time: 28/02/2010 15:04

Quote:

Original posted by puppymic at 28/02/2010 10:21
可能唔識用，我發揮唔到 CP8400 既威力，而且唔係幾忍到佢咁慢既儲相時間

The options of picture quality for CP8400 are from RAW, HI, EXTRA, FINE, NORM to BASIC. FINE is the version most people use and the storage speed is okay for an old camera like 8400. I use EXTRA and rarely RAW, not to mention HI, which is in TIFF format and is even more time consuming. I remember wrongly setting the camera in HI and it took me approximately 20 sec (I hope I don't remember it wrongly) to save a picture. I think EXTRA is good enough as you can depend on the picutre to do post treatment sufficiently well. So, Mandy, you can use that to take pictures next time.

Limit the ISO to 50 as far as practicable. The noise control is pretty okay there, to some extent better than the one performed by Ricoh GXR set at ISO 100.

As regards the lens, the ED glass in CP8400 is pretty faithful in producing images that are natural in color, appealing in tone and saturated in substance. I mentioned this because for images to be sharp and appealing, color renditioning is paramount. If the colors regenerated are thin, the linings of the object being shot will become indistinct and the overall ensemble of the shot will become murky. The consequence is unsharpness. My experience with CP8400 is that you can depend on its lens to do a good job for you on that.

Regards,
Pete

Author: puppymic Time: 28/02/2010 18:46

Pete, thank you for your advice, I will try this setting.

It takes long time to save a photo because I usually select the RAW format

Author: lwingkay Time: 28/02/2010 20:25

Quote:

Original posted by puppymic at 28/02/2010 18:46
Pete, thank you for your advice, I will try this setting.

It takes long time to save a photo because I usually select the RAW format

Try these as well:
1. Focusing: Select the autofocus mode
2. Focusing area selection: Select Manual to enable you to move the focusing spot to where you want to focus
3. Exposure: Select the centre-weight metering mode
4. Exposure compensation: Do it after you have completed framing.
5. Shutter release: Select the self-timer mode and use the 3-second one to avoid vibration.

Regards,
Pete

Author: cwchan Time: 2/03/2010 22:56

I suggest trying it again by taking raw format. Processing the DNG file also needs some practice and skill before getting good result.
I agree that the optical performance of Nikon 8400 is hard to beat so far among the dcs that I have tried.

Author: lwingkay Time: 3/03/2010 00:30

Quote:

Original posted by cwchan at 2/03/2010 22:56
I suggest trying it again by taking raw format. Processing the DNG file also needs some practice and skill before getting good result.
I agree that the optical performance of Nikon 8400 is hard to bea ...

Fully agreed to what you said and many thanks for the advice. Practice makes perfect. There is no way out except that. Pete

Author: lwingkay Time: 3/03/2010 10:21

Dear Chak Wing,
An extra to add about GXR, which I think you have already knowledlge about: GXR is equipped with a cable release. As usual, it is a very useful device on digital compact cameras that are intrinsically without the reflex mirror. It does away vibration in shutter release and makes fast shooting possible.
Regards,
Pete

Author: lwingkay Time: 14/03/2010 18:42

Further attempt with the GXR setup

Taken with Swarovski 80 HD STM, 30x and 45x-eyepiece, Ricoh GXR and its 24-72mm zoom lens
Mar 14, 2010 pm
ISO 100
The Chinese University of Hong Kong
Violet Whistling Thrush

1 Using a 45x

2 45x-eyepiece

3 30x-eyepiece

Author: lwingkay Time: 15/03/2010 22:07

Taken with Swarovski 80 HD STM, 30x-eyepiece, Ricoh GXR and its 24-72mm zoom lens
Mar 14, 2010 pm
ISO 100
The Chinese University of Hong Kong

4

Author: lwingkay Time: 20/03/2010 14:44

Taken with Swarovski 80 HD STM, 30x, Ricoh GXR and its 24-72mm zoom lens
Mar 20, 2010 am
ISO 100
The Chinese University of Hong Kong
Violet Whistling Thrush

6

Author: lwingkay Time: 27/03/2010 15:46

Swarovski 80 STM HD, 30x-eyepiece, Ricoh GXR and 24-72mm Zoom Lens
Sai Kung
Mar 27, 2010 morning
ISO 100

1

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