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Pillar of the Community
 2087 Posts |
An update:I know that a few people who use micro four-thirds, or Sony NEX/E-mount systems are interested in this lens. I've used it in the field and it performs well as an outdoor macro. The Half metre minimum focusing distance allows you to photograph insects a little( I mean a little!) easier. To do full one to one shots in the field my couple of times outdoors reinforced the need for a solid tripod, and a focusing rail. Indoors its a brilliant lens with coins that are the size of a quarter or less. With such coins the minimum focusing distance is actually really good. I can get all the lighting set up with plenty of room. Yesturday for the thread on Axial Lighting I photographed a Venetian ducat with a modern SIGMA EX 105mm Macro Lens. To be honest I didn't like the result. So this evening I blew the cob webs of the canon and this is the result. I am much happier with the photo( Taken using axial lighting) however I did notice something I hadn't picked up earlier: quite strong Vignetting. So instead of doing the usual circular crop I am posting the photo unedited. Look at the corners of the photo you will see considerable light fall off(that's the Vignetting) For coins of course its not a problem. However if any one wanted to use the lens outside it may be an issue they would want to be be aware of. Here is the picture:  Edited by austrokiwi
03/29/2014 2:32 pm
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Pillar of the Community
 United States
4038 Posts |
The darkening at the corners is "falloff" and can be corrected in photoshop or other programs. The information is there, it's just that there is less light hitting the sensor as you move away from the center. True "vignetting" is unrecoverable, as there is no information present.
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Pillar of the Community
2087 Posts |
Quote:
The darkening at the corners is "falloff" and can be corrected in photoshop or other programs. Huh? The other name for light fall off is Vignetting. At least that's what is in the photography books I have. In the photo I posted we can see Optical Vignetting caused by the lens its self. The photo was taken at F 11 So even though it seems mild, one could expect it to be much worse at larger apertures. Online you can find many references to it and this is a typical example: http://photographylife.com/what-is-vignettingEdited by austrokiwi
03/30/2014 05:26 am
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Moderator
United States
23522 Posts |
If it were optical vignetting the lens would do it regardless of what camera it was mounted on, as the lens itself is the cause. What you're looking at with the ducat is probably "natural" vignetting (natural illumination falloff), a physical manifestation described by the cosine fourth law of illumination falloff - correctable in post - or possibly pixel vignetting.
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Pillar of the Community
2087 Posts |
Its too dark to try outside ( for testing for vignetting). I am pretty sure its optical or, now coming in a close second) a mechanical function of the lens or the lens and the A7r's 35mm sensor. In the picture I posted you are looking at a coin that is 20mm in diametre. The photo was taken at a 1-1 ratio and this results in a lens, with adapter length, of 260mm long ( 1.5 inches shy of a foot). The picture dimensions are 7360 pixels by 4912 pixels. Its a huge picture covering a very small area. The lighting was very strong 60 LED lighting panel @ 5600 K. For the small area that was shot I don't think there is any likelihood of it being natural illumination fall off. I will try a white wall tomorrow and see what I get. I don't normally use the whole photo I usually crop out the background and replace it with a white field in Adobe elements. Useful discussion!
Edited by austrokiwi
03/30/2014 2:37 pm
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Pillar of the Community
United States
4038 Posts |
All I'm seeing is a little darkening in the corners. While this can indeed be called vignetting, that term is usually reserved for mechanical vignetting where the corners are black due to blockage of the light path, not slightly darkened due to normal optical properties of the lens.
Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
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Moderator
United States
23522 Posts |
What we call "optical vignetting" is also mechanical in nature, caused by lens elements further from the sensor physically shading elements closer to it.
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Pillar of the Community
2087 Posts |
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All I'm seeing is a little darkening in the corners. While this can indeed be called vignetting, that term is usually reserved for mechanical vignetting where the corners are black due to blockage of the light path, not slightly darkened due to normal optical properties of the lens. I am new to photography ( last 5 years) but I understand Vignetting is darkening in the corners: I am not sure you accessed the link I posted: here is the intro-text on that page: Quote:Vignetting, also known as "light fall-off" (sometimes spelled "light falloff") is common in optics and photography, which in simple terms means darkening of image corners when compared to the center. Vignetting is either caused by optics, or is purposefully added in post-processing in order to draw the viewer's eye away from the distractions in the corner, towards the center of the image. Depending on the type and cause of vignetting, it can be gradual or abrupt. There are a number of causes of optical vignetting â€" it can naturally occur in all lenses, or can be caused or increased/intensified due to use of external tools such as filters, filter holders and lens hoods. In this article, I will talk about each type of vignetting and also discuss ways to reduce or increase the amount of vignetting in photographs using post-processing software like Lightroom and Photoshop. Read more: http://photographylife.com/what-is-...xzz2xW349u5S I haven't had my second coffee yet but the sun was up and I photographed a white wall. As I said I hadn't had my second coffee so I didn't think adjust the exposure, or ISO from last night; when I had a quick try using room lights . The result of the failure to adjust last nights settings is that the photo is a little dark. In this test shot the lens set to 1-1 magnification and wide open(F4). The light falloff/Vignetting is readily noticeable {and it gives an antique look}. For coins its not a big deal and of course , as pointed out earlier, the effect can be edited out.  |
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Pillar of the Community
2087 Posts |
Well in real life who would even notice the light fall off: ( sorry its not a coin,looking at that spider through the focus magnification assist was creepy!)  So Edited by austrokiwi
03/31/2014 09:41 am
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Pillar of the Community
United States
4038 Posts |
I've never heard of minor natural fall-off referred to as vignetting, only intentional darkening created to give a particular "look" to the image, or mechanical reduction of field of view that gives the same effect. Lens reviewers call what you are showing "falloff", not "vignetting".
Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
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Pillar of the Community
2087 Posts |
Quote:
I've never heard of minor natural fall-off referred to as vignetting, Do an internet search nearly every result refers to lightfall off as being vignetting. |
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Pillar of the Community
United States
4038 Posts |
I did a search and I think the issue of misunderstanding is one of cause and effect, though in this case it is even more complicated from terminology perspective. "Falloff" is an effect of various phenomena, one of which is mechanical vignetting. "Vignetting" is one cause of falloff, but in the extreme it is an effect all by itself, and sometimes an intentional/artistic one. When I say "vignetting" I am referring to the effect of strong darkening around the periphery of a photo. When a lens reviewer says "falloff", he is referring to the minor reduction of light around the periphery of a photograph caused by physical phenomena. Terminology is tough when one of the terms is both cause and effect. You could even say "vignetting" is caused by vignetting! I'll stick with a simple definition of the effects and ignore causes. Otherwise you have to say all lenses vignette, which indeed they do, but it is useless to speak of them that way since it is a qualitative description. Instead, it is useful to say all lenses have falloff, which is quantitative, and thus has a full spectrum from 0%-100% to work with.
Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
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Pillar of the Community
2087 Posts |
I haven't posted any more infor on this lens but seeing that someone else has picked up a canon FD macro lens this may be a timely post. I like the 200mm but it has one nasty fault: chromatic aberration(CA). For those like me he aren't that familiar with photography terms: CA usually occurs in photos on areas that have the greatest contrast. at those points...the different light colours separate ( like in a prism) as they pass through the lens) leading to either red blue or a combination of both fringing. Heres a test photo of an NZ 3d ( about 17mm in diameter) it looks ok until you do some pixel peeping ( second photo) then as you become aware of what you are looking for you see it in parts of the coins design( first photo) My standard technique of using back lighting really begs for CA.   My standard camera these days is a Sony A7r and the canon FD lens is mounted using a novoflex adapter. I recently installed into the camera an application that allows me to programme in a lens compensation profile....I don't have all the technical knowledge I would like but luckily the camera allowed me to adjust the lens profile while using a subject. My best effort so far led to the following photographs( the second is a crop)   The CA is still evident but is greatly reduced...and the overall picture is better. I know lightroom will allow you to make similar adjustments after taking a picture... but its nice to be able to do it as you take a shot. All that said at the price one pays for some canon FD macro lenses some of you may well think it better to stick to more modern lenses where modern coatings deal with CA far more effectively. I must admit from time to time I consider selling the FD 200 simply because of the CA. I haven't so far as it has proved brilliant for close ups of parts of coins.....Should Zeiss produce a macro for the Sony A7r then I think the canon fd 200mm will have to be sold!! |
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Pillar of the Community
United States
4038 Posts |
I don't see a whole lot of difference. Both sets look good, though there is obvious diffraction softening.
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Pillar of the Community
2087 Posts |
Quote:
I don't see a whole lot of difference. Both sets look good, though there is obvious diffraction softening. I was a little disappointed as the posted photos don't really show how bad the CA is( its bad) click on the first photo to go to my photo bucket and you will see how serious it is. later to day I will repeat the photos...I hadn't picked up on the diffraction |
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Posted 03/29/2014 3:53 pm
