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Pillar of the Community
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I have a number of different lenses I use for macro work. I usually know from experience which one is best for which situation but I have never formally tested them against each other. Yesterday I thought I would do just that. I tested 7 lenses. 4 of the seven were bellows lenses and 2 of those were enlarger lenses. Of the three proper macro lenses only one was modern. The lenses:
- Meopta Anaret 4.5 80mm ( enlarger)
- Minolta 100mm F4 (Bellows)
- Olympus OM 135 F4.5 Bellows
- Schnieder Kreznach 5.6 150mm Componon( enlarger)
- Minolta MC 50mm F3.5
- Mamiya sekor C 80mm f4
- Sigma EX 105mm F2.8
For the comparison I used axial lighting( Edmonds 50/50 optically correct beam splitter). To ensure I had the best comparison I used focus peaking and focus magnification assist to ensure each coin was accurately focused. For ensuring the exposure level was comparable I activated Zebra ( set at 70) and used it to ensure the exposure was equivalent in each case ISO was 125. The pictures I am posting have all been edited and pasted into a 20 * 20 cm box. This limits what you can see as each of the pictures looks the same size. In reality some lenses , with the axial lighting weren't capable of filling the cameras sensor( camera is a Sony A7r with a 36*24mm sized sensor) The lenses that couldn't fill the senor fully were the Meopta 80mm, and the minolta MC 50mm. The minolta 100mm F4 bellows lens could almost fill the sensor it was just a little less flexible than the Olympus 135mm. I had previously owned a Canon FD200mm macro and a Minolta MD 100mm macro. The canon produced extremely bad Chromatic aberration with coins so I sold it. The minolta MD just never lived up to its reputation and the 50mm always outperformed it in picture quality. Before I show the pictures some comments. this comparison shoot clearly confirmed( for the first time consciously) to me that bellows with a focusing rail is far more user friendly, for coins, than normal macro lenses. The bellows gives much finer control over the magnification and seems to enable a much deeper field of focus ( DOF). With the focusing rail and using focus peaking I could get very fine adjustments which made them a pleasure to use. The "modern" Sigma 105mm EX macro lens was clearly the least user friendly in this regard. With the Sigma the coin would either be in focus or it would not( I was using a focusing rail with it also) the depth of field was just way too narrow. Of the lenses I used on the bellows: The meopta looks feels and performs like a toy. It was very cheap ( I purchased it mainly because it was sold with a very cheaply priced adapter that I wanted) It does produce reasonable pictures but in this shoot out it produced the worst and the pictures seemed to suffer from some sort of fogging or flare. I hardly ever use it The two best lenses used on the bellows were the minolta 100mm bellows lens and the much more modern Olympus Zuiko 135mm bellows lens. When it comes down to it I think the Olympus out performs the Minolta. The SK 150 mm enlarger lens is beautifully made ( it has around 15 aperture blades) and it is as smooth as silk; it is very useable. In picture quality it seemed, to my eye, to be just behind the minolta. Of the "Normal" macro lenses: The 50mm macro was the worst but this was due to the technique being used. With Axial lighting the 50mm just couldn't get close enough to the coin for a good photo. the beam splitter got in the way. I know when using a ring light or direct lighting the 50mm out performs the modern Sigma 105mm. The Mamiya 80 mm is a medium format lens so when taking coin shots on my full frame camera( smaller sensor than a medium format camera) only the centre of the optics are used. This usually results in much higher quality pictures, and that was the case with this test session. The Mamiya was the best performing "proper macro lens. I know from experience it also beats the Minolta MD 100mm Macro and the Canon Fd 200mm macro. For those who like pixel peeping heres the photos Meopta( ( picture has a fogged/Flared) Quaility  MInolta 100mm bellows lens  Olympus 135mm Bellows lens  Schneider Kreutznach 150mm enlarger lens  MInolta MC 50mm Macro lens( a truely yuk result)  Mamiya Sekor C 80mm  The sigma 105mm macro ( little better than the Minolta MC 50 mm)  I am probably repeating my self here; For the axial lighting set up bellows is the best way to go. My choice despite the fact I had to assemble the necessary adapter my self would be for the Olympus 135mm bellows lens. That said the much cheaper Schneider Kreutznach is also a very good performer. What shocked me was the poor performance of the one modern lens. I don't think it was technique. I think the Sigma lens is designed for out door use( flowers and insects) that design sees many compromises that make for great performance with non coin pictures...but for coins both the out put and the usability during the set up process were below expectation. Given the price differential the test has impressed upon me that a good quality enlarger lens on a bellows will out shoot a modern macro lens( for coins) Edit: to be totally fair to the sigma I should have noted this: To mount this lens I have to use Sony's LAE4 adapter. This turns the Sony A7r into Sony's version of a DSLR ( Sony has a fixed mirror technology they call such cameras SLT: Single lens translucent mirror). This adapter does reduce the amount of light getting to the sensor by half a stop. I don't think this has much effect on the actual picture as most of the bellows lenses I used are much slower than the Sigma( even when mounted on the adapter) Edited by austrokiwi
12/21/2014 03:53 am
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Pillar of the Community
 United States
4037 Posts |
Nice shootout of a wide variety of lenses. It's tough to make all the conditions consistent across such a wide variety of focal lengths, but your axial technique should help with this since the lighting doesn't change.
How are you keeping light from the back of the beamsplitter from affecting the image? This might impact different lenses differently.
Your not that the Sigma 105 is little better than the 50mm seems unfair, as it looks a lot better to me.
The longer lenses seem to be giving better results in this configuration. Could this be related to the lighting? The SK150 gives a really nice result with good colors, while the Minolta 100 seems to have excellent contrast. What level of postprocessing did each of these receive?
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Pillar of the Community
 2087 Posts |
Quote:
Nice shootout of a wide variety of lenses. It's tough to make all the conditions consistent across such a wide variety of focal lengths, but your axial technique should help with this since the lighting doesn't change. I used the zebra function on the camera(I don't believe Canon or Nikon DSLRs have it) Its normally a video camera function when the exposure gets to the set level zebra stripes are shown where the exposure matches the preset level in the image. I adjust the exposure until The zebra stripes are clearly evident across the coins surface. I used that method to ensure for each lens the same level of light was reaching the sensor. I did not adjust the lighting between each shot. I just had a 160 led ( 5500K: as registered by the cameras custom white balance) light panel providing the light for the beam splitter. Quote:
How are you keeping light from the back of the beamsplitter from affecting the image? This might impact different lenses differently. I constructed a wooden frame over which I stretched a black hand towel, nailed in place) that does the job of limiting unwanted reflections Here is the set up. The upper lights are on just for this picture normally they are off. The LED light is turned off in this picture  Quote:
Your not that the Sigma 105 is little better than the 50mm seems unfair, as it looks a lot better to me. My sigma is an earlier version and it really is awkward for the axial lighting set up. even at F11 the depth of field is very narrow. I found I have very accurate and "long" fine focusing ( using the stackshot focusing rail) with the longer lenses. Perhaps I was too hard on the sigma. My 'bias' against the sigma is from previous experience. In this set up the minolta 50mm is a waste of time. It needs to get so much closer to the subject than the beam splitter allows. Using direct lighting that 50mm excels and few other lenses( including the Sigma can match it) My example is NOS and is likely one of those manufacturing flukes that produce a phenomenal lens. From what I have seen my example performs better than usual Quote:
The longer lenses seem to be giving better results in this configuration. Could this be related to the lighting? The SK150 gives a really nice result with good colors, while the Minolta 100 seems to have excellent contrast. What level of postprocessing did each of these receive? The only post processing was to cut each "coin out of the back ground and to post it onto a white background file and adjust the size of the photo to match that background file(20cm *20cm) there was no editing of the actual coin picture. For my axial lighting set up the longer lenses definitely perform well. It might be the lighting and of course the design of the whole rig probably plays a significant part in that. When I am using direct lighting I prefer the Mamiya 80mm, on a tilt shift adapter, with 10mm of shift. The results are very good then |
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Pillar of the Community
United States
4037 Posts |
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My sigma is an earlier version and it really is awkward for the axial lighting set up. even at F11 the depth of field is very narrow. This is an interesting statement and worth discussing further... At a given magnification, and a given aperture, depth of field is a constant that is independent of the lens, focal length, camera, etc. Some folks talk about lenses that have more depth of field than other lenses, and yet based on optical physics this is not possible. However, something interesting to note is that the higher the lens quality, the more apparent depth of field becomes. A low resolution lens will be less sharp at the optimum focal plane, but as you move away from that plane the sharpness will not drop as rapidly as would a high resolution lens, since the lens is limiting the resolution, not the depth of field. This has the effect of making lower quality lenses have a larger "apparent depth of field". Ironically, folks who talk about the depth of field comparison between lenses usually favor lenses with more apparent depth of field, yet this is the incorrect perspective. I like to look at things "in the limit", and from that perspective a perfect lens, using a perfect camera capable of resolving down to the Abbe limit, has almost zero depth of field even at small apertures, if you define depth of field as a % reduction in resolution (circle of confusion). It is only the imperfections that give us usable depth of field, so the fewer imperfections, the less depth of field we have to work with... |
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Bedrock of the Community
United States
10045 Posts |
Interesting to see the results of different lenses--a good subject for this test too.  I'm assuming these photos are not at 100% crop--I see a noticeable difference between my 60mm and 105mm @ 100%--and often I use that size (1:1) for shots of overdates, etc. I like your results with the Schneider Kreutznach 150mm enlarger lens best. |
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Pillar of the Community
2087 Posts |
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At a given magnification, and a given aperture, depth of field is a constant that is independent of the lens, focal length, camera, etc. Some folks talk about lenses that have more depth of field than other lenses, and yet based on optical physics this is not possible. This has me really intrigued. Now I know F stop value is calculated by the formula N = F/D. N= the F stop value F is the focal length of the lens and D is the diameter. My instinctive application of the formula was to assume you added the extension length to the lenses focal length to get the "real" F value. That application of the formula had me assuming that as I increased extension length the DOF would increase. Two questions: is my application of the formula wrong? Am I confusing F stop value with T ( transmission stop value? Quote:
However, something interesting to note is that the higher the lens quality, the more apparent depth of field becomes. A low resolution lens will be less sharp at the optimum focal plane, but as you move away from that plane the sharpness will not drop as rapidly as would a high resolution lens, since the lens is limiting the resolution, not the depth of field. This has the effect of making lower quality lenses have a larger "apparent depth of field". Ironically, folks who talk about the depth of field comparison between lenses usually favor lenses with more apparent depth of field, yet this is the incorrect perspective. Accepting this I would say I am guilty of this. But! What you have said has made me also regard the possibility of the focusing method I was using creating the impression. I was using focus peaking rather than trusting my eye. the focus peaking was giving me the "on/off" perception of the sigmas ability. Focus peaking works on contrast detection ( highly typical of the current generation of Mirrorless cameras) the SK, minolta 100mm bellows and the Olympus were all showing much better contrast( to my eyes). The sigma when mounted on the A7r via the adapter can also be focused by phase detection I have noticed in the past when I set the camera to Auto focus as noisy and slow as it is the Sigma performs better( auto focus uses phase detection) I will try later today with the sigma again and will turn off focus peaking and just rely on the Phase detection indicators. Clearly my impressions may well have been shaped by my preference for focus peaking( contrast detection). In effect I now suspect my test method was favouring one type of lens! Quote:
I'm assuming these photos are not at 100% crop--I see a noticeable difference between my 60mm and 105mm @ 100%--and often I use that size (1:1) for shots of over dates, etc. Most definitely not 100 % crop. these are just as they came out of the camera Quote:
I like your results with the Schneider Kreutznach 150mm enlarger lens best. I have gone back over the photos and I have to acknowledge that the SK certainly does seem to have the edge. As I said its a beautifully made piece of optics. Its real quality. It doesn't have modern coatings( as far as I know) but for my copy stand set up that does not seem to be an issue of any import. I also have the much better SK 210 large format enlarger lens.....but its incredibly "long look" just makes it unmanageable on my set up. When I get the right amount of extension ( Minimum is bellows at full extension plus extension rings) I bring in so much more physical instability that just breathing in the same room seems to create annoying vibrations. Then bring into play the A7rs legendary shutter! Edited by austrokiwi
12/22/2014 01:54 am
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Pillar of the Community
2087 Posts |
Following the feed back comments I have received so far I re tested the MInolta MC 50mm ( is it as good as I think it is?) and the sigma 105mm ex. I won't comment, on image quality, this time I want to get feedback from more objective eyes. First off the sigma 105mm with axial lighting focus peaking disabled and I used the cameras phase detection to indicate focus  Second shot Same as the first except using auto focus( phase detection)  For the next shots I went to "direct lighting" I had to reset white balance. For the best lighting 2 lights( 1 on the left and 1 on the right) were pointed in the general direction of the coin. ]The remaining two lights were pointed at the sloping ceiling so that their light was bounced on to the coin. The 50mm minolta really showed the limitations of its focal length, in regards to lighting, it had to moved much closer to the coin and effectively shaded it. First: the sigma 105 EX with auto focus:  Then the Minolta MC50mm ( with focus peaking back on):  |
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Pillar of the Community
2087 Posts |
This evening I was playing around with lighting set ups I was trying to set up my lighting to get true to life pictures. I discovered some disturbing behavior from the Olympus 135mm Bellows lens. Wide open I was getting a good picture but closing down the aperture I started to get ghosting/Flaring in the centre of the picture. I tried the SK 150mm enlarger lens and the Minolta 100 mm bellows lens and didn't have the same problem. After several attempts I am now pretty sure that when I close the aperture on the olympus I am getting a bad dose of Sensor reflection( that wasn't evident when I was using Axial lighting: Heres some unedited pictures: First up Minolta 100mm F4 @ F8  The Olympus @F8  The Olympus Wide open:  Actually I think there is sensor reflection in this last shot. |
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Pillar of the Community
United States
4037 Posts |
Interesting. I've seen this contrast problem on lenses wide open, but never closed down.
Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
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Pillar of the Community
2087 Posts |
rmpsrmps is your term contrast problem the same as sensor reflection? I am pretty sure that the combination of the high angled lights plus a shiny coin is seeing an annoying proportion of light being reflected off the cameras sensor back to the rear lens element:
When the aperture is closed it makes that rear lens element act even more like a mirror. I started to think sensor reflection when I removed the coin and waved my hand in front of the camera a White circle was clearly above my hand and remained in the same part of the picture. Its probably a fault created by the design of my camera( Sony A7r) in combination with the the lens design (Modern native lenses are designed to prevent sensor reflection becoming a problem).
Evening edit. I am perplexed. Yesterday was the first time I had noticed the Contrast/sensor reflection problem. I had been using the Olympus on my minolta bellows, but I also have the Olympus made extension tube. I don't usually use that tube because it doesn't give the magnification I want( maximum with the 135mm is 1-3). To explore the problem further I tried the extension tube....The lights were set up exactly the same way, same coin, no sensor reflection!! So I examine the constructed adapter that allows the lens to attach to the Minolta MD bellows. Looking from the camera end I can see some nice shiny silver metal at one of the joining points( cheap chinese extension ring element) Even though this ring of reflective metal is positioned at the opposite end of the bellows to the camera it seems to be the only possible culprit I can see. Next week , when its open, I will head off to my favourite analogue camera technicians shop and get some black camera paint. It will be interesting to see if that "silver" ring is really the problem. The only way light could get to that ring would be from the sensor
Edited by austrokiwi
12/29/2014 11:24 am
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Pillar of the Community
United States
4037 Posts |
AK...yes, any light that hits the sensor that is not from direct image rays will reduce the contrast. Our bellows systems have an advantage here since they push the closest lens elements (and aperture) far away from the sensor. Any small amount of light that reflects off the sensor must travel all the way to the lens, then all the way back, and be perfectly aligned in order to cause a problem. Even then, sensors reflect only a small part of the incident light. You're seeing such a high level of contrast reduction that this could not be the cause. As I said earlier, usually this problem occurs wide open, and is due to light hitting the sides of the extension tubes / helicoid and reflecting to the sensor. But since your problem is occurring stopped-down, this could not be the problem either. Most likely there is some amount of reflection off the aperture blades, which is re-reflected by the surface of the lens closest to the blades on the objective side. Are the blades of the Olympus lens dark or bright? Are they oily, so that they are shiny when they are stopped-down? Can you remove the front element and replace the aperture with a fixed stop as a test?...Ray
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Pillar of the Community
2087 Posts |
rmpsrmps. I am a bit nervous about pulling the lens apart( the lens is not cheap). There are no signs of oil . Certainly the problem is aperture related. The fact it only occurs with the bellows and not the extension tube( http://www.alanwood.net/photography...o-tube.html) points to a factor in the bellows set up. So as a first step I want to see if it is that ring of metal....in my self assembled adapter. |
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Pillar of the Community
2087 Posts |
OK I worked out what the problem is with the Olympus 135mm bellows lens,and with just a day left on the ebay return period! The rear lens group has separation right in the the centre of the field of view. The problem was less obvious when wide open because light was travelling through the outer parts of the lens. Stopped down and the light path was only through the area of separation. It was really hard to spot the separation bubble( thats what it looks like). When I did the standard lens test, looking through the lens wide open looking at a light, all I could see were a few specks of dust( normal) and the lens looked as clear as fine crystal. ONly spotted the separation( I wasn't even sure what it was until I checked photos of examples on the internet), when I closed the aperture down to F45 and looked through the rear of the lens at an oblique angle. I could then see a silvery luminescent disk that was somewhat like a transparent cataract. Its really annoying because this lens really performed the way I wanted. Hopefully it will go back ok and then I can get another example. I already checked and there are three examples being sold locally. I will go examine them my self after this investment in experience. Edited by austrokiwi
01/10/2015 06:21 am
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Posted 12/21/2014 1:10 pm
