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Old Oct 20, 2005, 12:26 AM   #21
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jcr wrote:
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Ok, 6T is to stay , and what about DCR250 ? any opinion with FZ30 ? It shure was super with FZ20, but with your statement left me thinking again...:? I don't have it but was on purchase list for FZ20 already...
I have both DCR250 and MSN500. They are very good on shorter focal length cameras and have problems with long focal length super zoom cameras. The basic problems are edge sharpness and edge achromatic aberration, especially at the closest focusing distance. Moreover, due to their small diameter, corner light fall-off is visible. Therefore, think carefully to see if you can accept any high diopter close-up lenses. For professional uses, +4 diopter (e.g., Canon 250D) is perhaps the upper limit for excellent image quality. Beyond that image quality reduces as diopter increases. On the other hand, if you only print small size (e.g., 4x6) and you don't shoot many flat objects, nearly any doublet close-up lens would be fine, and stacking two of them would still get you reasonable result, i.e., two +4 becoming a + 8. My Canon A95 information page has further information on the use of close-up lenses.

A few words about a problem. Some misinformation about teleconverter power initially generated on DPreview.com now has started showing up here on this board.

(1) Brand A 1.7X (or 1.5X) converter is not 1.7X (or 1.5X). Don't be misled by this wrong concept. Tele and wide angle converter power is not measured as those misinformation state. The power of a teleconverter is defined, independent of the camera being used, as the ratio of the focal length of the "front" glass and the focal length of the "rear" glass. Moreover, camera lenses are calibrated at infinity rather than at close range. If brand X lens is claimed to be 1.7X, it is possible, due to rounding and manufacturing tolerance, that the actual power measured without a camera would be 1.72X or 1.67X. The same 1.7X converter used on a different camera with a different focal length CAN yield different power "measured" by images taken with that camera. In other words, a 1.7X converter on camera A could be measured as 1.5X at close distance, 1.65X at long distance and 1.7X at infinity (because this is the standard). If the same 1.7X lens is mounted on another camera with different focal length, the "measured" magnification can be 1.8X! Here are the discussions of this misinformation: http://forums.dpreview.com/forums/re...ssage=14156233and http://forums.dpreview.com/forums/re...ssage=14214535 Just skip all the calculation, which is for those who can follow, and jump to the conclusion part. Then, you will see what I said.

(2) The gap between the rear glass elements and the camera lens front glass element has to be x.yz mm, or to be as close as possible. This is also a misinformation. This gap depends on so many factors, which include the optical formulas of the converter and the camera being used, and, as a result, there is no fixed value. For example, some Nikon converters used on some Canon cameras (e.g., A95 and A80) requires a larger gap (i.e., moving the lens away from the camera lens). Another good example is the Olympus WCON-07 0.7X wide angle. If it is too close to FZ-30'scamera lens, you will see a blurred spot at the center, perhaps (just perhaps) due to field curvature. In this case, the WCON-07 has to be moved away from the camera. This problem surfaced initially on Asia's BBS/forum discussion right after the FZ-30 was released, and many proposals were suggested to solve the problem. Please see this thread for more information: http://forums.dpreview.com/forums/re...ssage=15143199 Now I see more solutions available.

On the other hand, some wide angle converter lenses have to be very close to the camera lens in order to avoid vignetting at the corners, the Raynox DCR-6600 being a good example. The problem comes from the image circle formed by the lens being a little smaller than the entrance pupil (i.e., the hole for the sensor to see through at maximum aperture, in this case). Some DIY solutions to this type of problem may include the removal of the 1 or 2 mm from the lens tube (or the mounting thread) or do whatever you can to bring the lens closer to the camera lens.

(3) The gap would affect the image quality. This holds in the most general way; but, it is not always true in the micro way. When you hold a converter in front of you and see through from the center, you will find the center portion being sharper than the edge portion. This is completely normal due tothe rules of physics. If a lens is moved too far away, the cameras lens will pickup the peripheral area which is not sharp. However, this will take a rather large distance movement. In general, the movement of 1mm is perhaps still within the tolerance of manufacturing. So, just don't worry that 1mm gap difference. Most claims in this regard do not have clear evidence that can show image quality difference. In fact, some are purely speculation or just "claims." If you wish to try it, you may mount a converter specially made for a particular camera. Then, take an image after each 1/4 turn to see how much difference you can find.

An updated version of my teleconverter comparisons is now part of my to-be-announced FZ-30 user guide here: http://www.cs.mtu.edu/~shene/DigiCam/User-Guide/FZ-30/ There will be four to five testing scenes that cover most commonly shooting occasions. Currently, only the second scene is online and I am working on the 1st scene. Other tests will be posted in the near future.

Hope this helps clear up some doubts.

CK

http://www.cs.mtu.edu/~shene/DigiCam

Nikon Coolpix 950/990/995/2500/4500/5700, Panasonic FZ-10 and Canon A95 User Guides




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Old Oct 20, 2005, 9:14 AM   #22
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shene:

Thank you for your user guides.

Have you done any test on Raynox DCR-6600? I would be interested to know how does it compared to WCON-08B (sharpness, light fall-off, vignetting, etc.) on both FZ20 and FZ30. I currently have WCON-08B and like its quality but sometimes find it not wide enough. So I am debating whether I should sell it and get HD-6600 or not and would like to hear your professional opinion. I will be using it with both FZ20 and FZ30.

Thanks.
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Old Oct 20, 2005, 9:31 AM   #23
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jcr wrote:
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LoveLife wrote:
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Keep your 6T andI believe the DCR250 will perform better on the FZ30 then on the FZ20. The lens base is positioned 5.84mm from the front bezel on the fz10, 15 and 20, and 3mm from the front on the FZ30. This should result in sharper edges. I am going to make a special ring for the DCR250 that will bringthe lens displacement to. 78mm. In the mean timeI am going to do some tests today using the standard spring mount.


ok, I'll maintain DCR250 on purchase list...I'm trying to figure how can You tell such exact distances....:?

feel free to post results from that test...:|
Zooms do great macros

Here are the test results between the FZ10 and the FZ30 closeness counts $20.00 bill

The reason the pictures are not sharp enough is because the magnification exceeds the definition of the image.



These are two test shots of the DCR250 with the FZ10 w/ CRing adapter and FZ30
Both are done with the standard Raynox spring mount. From what I see my special TRing will produce a better image. I do not have the tools to mock up the results.
I tried to make the shots asclose as possible. Can you see a difference?

I sure can.


FZ10 w/ DCR250
Aperture: f/4.0
ISO: 100
Focal Length: 72mm (432mm 35mm)
Exposure Time: 0.2s (10/50)
JPEG Quality: fine

FZ30 w/ DCR250
Aperture: f/5.0
ISO: 100
Focal Length: 88.8mm (444mm 35mm)
Exposure Time: 0.5s (10/20)
JPEG Quality: fine


ONE



TWO



ONE CROP



TWO CROP





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Old Oct 20, 2005, 9:58 AM   #24
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skyrocketfw wrote:
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Sorry Lovelife, I have one more question.

How is the images quality produced by dcr-6600? Are they better, worse or the same as those produced by wcon-08b?

Thanks.


On the FZ30 the DCR6600 with a special ring or the new HD6600 -55produce the best widest images with the least amount of distortion and no vignetting.You just can not do any better on this camera.



Notice the stop sign?

Leica at 35mm





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Old Oct 20, 2005, 10:21 AM   #25
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skyrocketfw wrote:
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LoveLife wrote:
Quote:
Both the DCr1540 and the DCR6600 are currently 52mm mounts. They will not perform satisfactory on the FZ30 with a conventional 55-52step-down ring, which positions them 4mm from the Leica bezel. They excel when mounted in a special ring that I am making. Prior to the rings arrival I have glued both lenses into 55-58mm step-up rings, which brings the lens mount .98mm from the Leica Bezel. I would have to do a side by side to determine which one is better. There are many variable to the question. The money issue is not significant about $15.00. It has been awhile since I saw the effective rate numbers for each lens. I believe the TCON17 is 1.59 and the Raynox is 1.51. Olympus is overzealous with their magnification factors. The DCR2020 2.2x effective rate 2.12x works much better on the FZ30. I believe it is because of the reduced magnification FZ 30= 420 vs. FZ20=432 or in 2020 terms 924mm vs. 951mm. It has the longest reach but needs good lighting to excel.
Quote:
Thanks LoveLife.

So between DCR-1540 with your new ring and TCON-17, which onedo you think is better?
I will not know until I do some testing.


LoveLife wrote:
Quote:
The HD6600 (55mm mount) is the exact same lens as the DCR6600 (52mm mount). If you have a CRing adapter the results with each lens will be identical. That reason is the 62mm CRing adapter uses special 66-55mm CRings or 62-52mm CRings to change the mount with zero change to lens base displacement. If you use another adapter with step down rings the results will be terrible. The CRing adapter has a fixed lens base displacement of 2.84mm regardless of configuration.
Quote:
So the different mount size wouldn't make any different. I was hoping that it might eliminate the vignetting.

The lens mount change between 52mm and 55mm will give the same results if both are positioned the same distance from the front bezel.

LoveLife wrote:
Quote:
I have not tested any macros on the FZ30 but I feel the added 4mm standard ring distance will efect the edge quality.

The best bet is the Nikon 4T with the new ring.

Quote:
Do you mean 4T would be better than 6T?
Quote:
I have no proof now but I believe that the 4T with the special ring will perform better the 6T. I can drop the 4T lens displacement to .78mm because it is smaller mount and fits inside the 55mm cavity. The 6T at 62mm must be positioned outside. I am going to make a 3.8mm 55-62mm ring but do not know if that will be a factor. I would not get rid of the 6T with a step-up ring because it a fine macro lens and I do not have any proof.
[/quote]
Quote:
Will you be making new ring for 6T, TCON-14B as well


Thanks.
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Old Oct 20, 2005, 12:10 PM   #26
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shene wrote:

(3) The gap would affect the image quality. This holds in the most general way; but, it is not always true in the micro way. When you hold a converter in front of you and see through from the center, you will find the center portion being sharper than the edge portion. This is completely normal due tothe rules of physics. If a lens is moved too far away, the cameras lens will pickup the peripheral area which is not sharp. However, this will take a rather large distance movement. In general, the movement of 1mm is perhaps still within the tolerance of manufacturing. So, just don't worry that 1mm gap difference. Most claims in this regard do not have clear evidence that can show image quality difference. In fact, some are purely speculation or just "claims." If you wish to try it, you may mount a converter specially made for a particular camera. Then, take an image after each 1/4 turn to see how much difference you can find.


I see posts of how close a converter lens should be mounted from the camera's front lens. i.e. Iscloseralways better oris there an optimum gap [distance] to mount a specific lens from the FZ30: for say the TCON 17 and other popular lenses? What are the reference surfaces to measure the gap? Another question: What is the pitch of the mounting threads of the lenses so I can figure out what is the change in the gap is for each 1/4 turn?

Thank you

Stan
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Old Oct 20, 2005, 1:23 PM   #27
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LoveLife wrote:
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On the FZ30 the DCR6600 with a special ring or the new HD6600 -55produce the best widest images with the least amount of distortion and no vignetting.You just can not do any better on this camera.


Thanks LoveLife. How about sharpness and light fall-off when using DCR-6600 in comparison to when using WCON-08B on both FZ20 and FZ30?

Do you have photo taken by WCON-08B as well? I would like to see how much wider DCR-6600 produced.

I am deciding whether to sell WCON-08B or not. I will be using it with both FZ20 and FZ30, so which one do you think is the better choice?

Thanks.
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Old Oct 20, 2005, 3:05 PM   #28
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LoveLife wrote:
Quote:
Zooms do great macros

Here are the test results between the FZ10 and the FZ30 closeness counts $20.00 bill

The reason the pictures are not sharp enough is because the magnification exceeds the definition of the image.



These are two test shots of the DCR250 with the FZ10 w/ CRing adapter and FZ30
Both are done with the standard Raynox spring mount. From what I see my special TRing will produce a better image. I do not have the tools to mock up the results.
I tried to make the shots asclose as possible. Can you see a difference?

I sure can.


Witch one is fz10 and Fz30 ? for me the "One" is shaper
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Old Oct 20, 2005, 3:07 PM   #29
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shene wrote:
Quote:
I have both DCR250 and MSN500. They are very good on shorter focal length cameras and have problems with long focal length super zoom cameras. The basic problems are edge sharpness and edge achromatic aberration, especially at the closest focusing distance. Moreover, due to their small diameter, corner light fall-off is visible. Therefore, think carefully to see if you can accept any high diopter close-up lenses. For professional uses, +4 diopter (e.g., Canon 250D) is perhaps the upper limit for excellent image quality. Beyond that image quality reduces as diopter increases. On the other hand, if you only print small size (e.g., 4x6) and you don't shoot many flat objects, nearly any doublet close-up lens would be fine, and stacking two of them would still get you reasonable result, i.e., two +4 becoming a + 8. My Canon A95 information page has further information on the use of close-up lenses.

A few words about a problem. Some misinformation about teleconverter power initially generated on DPreview.com now has started showing up here on this board.

Thanks Shene, for the good explanation and those transcriptions
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Old Oct 20, 2005, 3:37 PM   #30
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stnkline wrote:
Quote:
shene wrote:

(3) The gap would affect the image quality. This holds in the most general way; but, it is not always true in the micro way. When you hold a converter in front of you and see through from the center, you will find the center portion being sharper than the edge portion. This is completely normal due tothe rules of physics. If a lens is moved too far away, the cameras lens will pickup the peripheral area which is not sharp. However, this will take a rather large distance movement. In general, the movement of 1mm is perhaps still within the tolerance of manufacturing. So, just don't worry that 1mm gap difference. Most claims in this regard do not have clear evidence that can show image quality difference. In fact, some are purely speculation or just "claims." If you wish to try it, you may mount a converter specially made for a particular camera. Then, take an image after each 1/4 turn to see how much difference you can find.


I see posts of how close a converter lens should be mounted from the camera's front lens. i.e. Iscloseralways better oris there an optimum gap [distance] to mount a specific lens from the FZ30: for say the TCON 17 and other popular lenses? What are the reference surfaces to measure the gap? Another question: What is the pitch of the mounting threads of the lenses so I can figure out what is the change in the gap is for each 1/4 turn?

Thank you

Stan
I do not work with generalities I work with specifics. I have only found one lens that requires a greater distance to remove a center fog spot the WCON07 on the FZ30. I do not care about "ΒΌ turns" or statements or "1mm is perhaps still within tolerance" statements. I prefer testing. We are talking not talking 1mm. Step ring = 4mm, CRing adapter =2.84mm. Special TRing. 78mm. The thread pitch on 99% of all lens add-ons and filters is .75mm.
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