Cosina 28 f2.8 đánh giá
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For starters, this lens is a Cosinon. Cosina has made some good 28mm's for Vivitar and here they've made a good lens for Petri. Show I'll get right to it. This lens is reasonably sharp at f2. Contrast is excellent wide open. It is not soft. Chroma is very well controlled. Fringing is well controlled. Flare is also well controlled. Shooting directly into the sun will cause a loss of contrast and a few heaxagonal spots but flare is non existent with the sun just out of frame. Harsh lighting results in some highlight clipping. On the subframe Eos M3 there is little distortion. Color rendition is excellent. Bokeh is smooth and bokeh fringing is barely noticeable in real life shooting. However, in close focus shooting it can be seen up to f2.8. It focuses down to 8" and is well dampened. On the M3 it makes a good walk around lens. Focusing is easy through the viewfinder and it balances perfectly in the hand. The Minolta 28mm 2.8 M-Rokkor was released alongside the Minolta CLE and is one of the most affordable 28mm M-mount lenses these days. Unfortunately it is also infamous for developing “white dot issues”, probably the main reason for this lens still being affordable on the used market. What is this all about and is it still a good idea to buy this lens or should you rather stay away from it? Let’s find out. Lens is being tested on 42mp Sony A7rII and 24mp Leica M10 Sample ImagesYou can find most of the sample images in full resolution here. Contents DisclosureThe Minolta 28mm 2.8 M-Rokkor was kindly provided free of charge by our reader Victor for reviewing purposes. Thanks a lot! As this sample of the lens wasn’t in perfect condition I asked my friend Juha if I could use some of his pictures for the review, as he owns a sample in better condition. His pictures are those taken on a Sigma fp. SpecificationsThe Minolta 28mm 2.8 M-Rokkor has the following specifications:
You can buy this lens from ebay.com (affiliate link) expect to pay $200 for one full of white dots and $450+ for one in actually good condition Handling / Build QualityIn terms of casing design and colors the three Minolta M-mount lenses strongly resemble the style of original Leica M-mount lenses of that era. When comparing this 28mm 2.8 (and also the 40mm 2.0) to e.g. my similarly old Leica 90mm 2.0 from 1987 (or modern Voigtländer and TTArtisan lenses) the build quality does not feel as nice though: the focus rings of the Minolta lenses have a rather low resistance and both their helicoids show a bit of slack. I don’t know if they have always been like that or if it is simply because they have been used a lot over the past 40 years though. The focus ring turns ~110° from its minimum focus distance of 0.8 m to infinity. The aperture ring features equidistantly spaces half-a-stop click-stops between f/2.8 and f/22. All the markings are engraved and filled with paint and most parts of the outer barrel feel like they are made from metal. I am not 100% sure about the small focus tab though, it feels like that one is made from plastic. An issue very common to encounter with this lens are white dots behind the edges of the front element and apparently also some condensation that shows up as oil on the rear of the front element. This very lens has been taken apart and cleaned by its owner, but you can still see traces of this issue and you can also still notice a negative impact on this lens’ flare resistance, as I will show you in the corresponding section. While there were retractable screw-in rubber hoods available for the 40mm 2.0 and 90mm 4.0, the hood for this 28mm 2.8 is a round vented one that attaches via a bayonet. The Minolta 28mm 2.8 M-Rokkor brings up the correct 28mm framelines on the Minolta CLE. On the Leica M6/M10 it brings up the 35/135mm pair, you can however use the frame preview lever to display the 28/90mm pair. As long as you don’t use a hood there is only minimal rangefinder blockage in the lower right corner when the lens is set to its minimum focus distance. With the lens set to infinity there is hardly any. While compact, this 28mm 2.8 is neither as small as its longer sibling the 40mm 2.0 nor the Leica 28mm 2.8 Elmarit-M or its newest competitor, the Voigtländer VM 28mm 2.8 Color-Skopar. The lens can of course be adapted to modern mirrorless cameras. When coupled with a Sony E-mount or Nikon Z-mount camera you can e.g. use the TTArtisan 6-bit adapter to give it Exif data or the Techart LM-EA9 to equip it with autofocus. Vignettingf/2.82.9 EV f/4.02.1 EV f/5.61.5 EV f/8.0-f/221.3 EV The vignetting figures are not low, but in line with what is to be expected from a compact 28mm f/2.8 lens. The Voigtländer VM 28mm 2.0 Ultron MK II performs a bit better at f/2.8 but worse stopped down. The Brightin Star 28mm 2.8 shows very similar vignetting figures. It is recommended to have a look at this article first to get an idea how this brightness graph works. SharpnessFocus shiftThis Minolta 28mm 2.8 M-Rokkor shows no visible focus shift even on 42mp cameras. infinity (42mp Sony A7rII, 24mp Leica M10)Now on the Leica M10 this lens shows a very fine performance with good resolution across the whole frame from f/2.8. On the Sony camera (this would also apply to other mirrorless cameras with a thicker sensor stack) the situation is a bit different, here the lens needs to be stopped down to f/8.0, or better f/11, to look as good in the corners as on the Leica camera at f/2.8. The problem is that many of these lenses suffer from haze, allegedly caused by oil on the rear of the front element, significantly decreasing the overall contrast and also saturation. This becomes very obvious when comparing it to a modern lens without any such issues: Leica M10 If you look closely you will see this issue in many of the sample pictures and I also added a few, where it is very obvious, to the flare resistance section. close distance (0.8 m, 42mp Sony A7rII)Sony A7rII | Minolta 28mm 2.8 | 100% crops A minimum focus distance of 0.8 m is pretty long for a 28mm lens. Modern non-M-mount 28mm lenses usually focus as close as 0.3 m and even the modern M-mount lenses can often be focused down to 0.5 m at least. At close distances at f/2.8 the image is a bit soft, but stopping down to f/4.0 already makes a big difference. Flare resistanceAs I told you before this lens is known for having issues with white dots showing up behind the front element and that this very sample has been cleaned by its owner, but as I have also shown you the lens is not perfectly clean, so we will see what the performance in this category is like now. Leica M10 | Minolta 28mm 2.8 There is a bit of a blooming effect around strong point light sources which I think might be because of the aforementioned issues. With the sun barely outside the frame there is that one position leading to huge veiling flare, but this can easily be avoided by slight reframing. As I already told you in the sharpness section what is a bit more of an issue (and I encountered this frequently): even in overcast and seemingly unproblematic conditions there is often some haze stealing away a lot of the contrast, here easily visible on the building in the back and the tree line on the right: Coma100% crops from extreme corner, Leica M10, focus at infinity hard stop We saw good corner resolution at infinity, so coma shouldn’t be a huge problem. At f/2.8 we do some – which is probably the reason for the lower contrast in the corners we saw in the sharpness section – but the situation improves noticeably at f/4.0 and at f/5.6 the corners are completely clean. DistortionThe Minolta 28mm 2.8 M-Rokkor is almost distortion free. SunstarsLeica M10 | Minolta 28mm 2.8 M-Rokkor | slight crops This Minolta 28mm 2.8 is using 10 straight aperture blades like many of the Voigtländer VM/E and Zeiss ZM/Loxia lenses, leading to pretty nice sunstars between f/5.6 and f/16. At f/2.8 and f/22 the opening is perfectly round, so no sunstars at these settings. If you want to learn more about this topic have a look at this article. BokehA maximum aperture of f/2.8 coupled with a minimum focus distance of 0.8 m in a 28mm lens is pretty bad news if you are after some nicely blurred out of focus backgrounds. For faster (and closer focusing) 28mm lenses that are more suited to the task of environmental portraits best have a look at the alternatives section at the end. Chromatic AberrationslateralSony A7rII | Minolta 28mm 2.8 | f/11 The Minolta 28mm 2.8 M-Rokkor shows only a low and easy to correct amount of lateral CA. longitudinalNow bokeh fringing cannot really be a problem because there is not a lot of bokeh to begin with, but what about purple fringing? Leica M10 | Minolta 28mm 2.8 | 100% crops You have to look really close to spot some faint purple fringing in an extreme scenario like this and then you will only be able to spot it at f/2.8, not stopped down to f/4.0 or further. A good performance. Conclusiongood
Generally, especially considering this Minolta 28mm 2.8 M-Rokkor was meant as a “low cost” 28mm lens when it was released, the optical performance is really quite good. On film or digital Leica M cameras already at f/2.8 the resolution is really good across the whole frame at infinity without any obvious midzone dip. When used on a Sony E or Nikon Z camera stopping down to f/8.0 or better f/11 to get some details in the corners is advisable though. On top of that this lens is small and lightweight, distortion is well corrected, CA correction is good, sunstars stopped down are nice. So what is not to like? Well, there are two things to be aware of: The not so significant one is the minimum focus distance of 0.8 m. This is way too long for me in a 28mm lens and this would be reason enough for me to pick one of the alternatives already. The more significant one is the white dot issue, especially because it seems to be a recurring problem. Even if you buy a clean lens today it will most likely develope some issues over time. I am not exactly sure what is the problem. Some people say the paint dissolves and can lead to oil residue on the rear of the front element, others also claim that if this isn’t fixed, it will lead to corrosion of that element and permanently damage it. Either way, I think it has a strong negative impact on the flare resistance and general contrast of this lens, as I had to deal with veiling flare in situations where I really didn’t expect it. Now if you are a bit of a tinkerer and you find one of these lenses in such a condition that you are able to restore it, this can be an interesting, affordable 28mm option for you. For everyone else the latest Voigtländer VM 28mm 2.8 Color-Skopar Type II is probably the better option, see the Alternatives section below. You can buy this lens from ebay.com (affiliate link) expect to pay $200 for one full of white dots and $450+ for one in actually good condition AlternativesI reviewed quite a few 28mm M-mount lenses ranging from f/1.4 to f/5.6 all listed on this page and I will only talk about the real obvious alternatives here. Voigtländer VM 28mm 2.0 Ultron MKII: Probably the best balanced 28mm lens for M-mount. It is similarly sized and only 50g heavier than this Minolta lens, but a full stop faster, focuses down to 0.5 m and has nicer build quality. I can hardly think of a category where this Voigtländer lens doesn’t perform better, not too surprising considering it is a 40 years younger design. buy from B&H | ebay.com | ebay.de (affiliate links) for $799 Voigtländer VM 28mm 2.8 Color-Skopar: As of 2023 this is Cosina’s latest 28mm lens. It is noticeably more compact and even a bit lighter than the Minolta lens and except for the high vignetting its performance is pretty much impeccable. It costs almost as much as the aforementioned 28mm 2.0 though, so if you are not really after having the smallest lens, I would recommend to go for the faster f/2.0 one instead. buy from ebay.com | B&H (affiliate links) for $699 Leica 28mm 2.8 Elmarit-M: This Leica lens sits inbetween the two aforementioned Voigtländer lenses size wise. It does also offer a complex optical design and according to Fred Miranda’s comparisons the Voigtländer is sharper in the center at wider apertures whereas the Leica is sharper in the midframe and show slightly less vignetting. I am not sure how they compare with regards to flare resistance though where some Leica lenses disappointed me quite a bit in the past. buy from B&H | ebay.com | ebay.de | amazon.com (affiliate links) for $2795 There are also a Zeiss ZM 28mm 2.8 Biogon and a Konica Hexanon-M 28mm 2.8 available, but I don’t know enough about either to tell you how they compare to this Minolta. For E-mount and Z-mount users, lenses like the Sony FE 28mm 2.0 and Viltrox 28mm 1.8 AF are probably better choices, if you haven’t sufficiently covered this focal length in one of your zoom lenses anyway. Further Sample ImagesYou can find most of the sample images in full resolution here. Further Reading
Support UsDid you find this article useful or just liked reading it? Treat us to a coffee! The following two tabs change content below. My name is Bastian and I am your expert here when it comes to ultra wide angle lenses, super fast portrait lenses (ranging from a 50mm f/0.95 to a 200mm f/1.8) and I also have reviewed way too many 35mm lenses. Don't ask me anything about macro or wildlife shooting though. |
