50 mm Lenses - They are all good; which is better?

Valentin - Unlike some other companies, Pentax uses the same high quality standards for both the FA 50/1.4 and FA 50/1.7 lens. Any of them is a good one. . .

The most important differences you will notice between the two FA will be: 1) the brighter viewfinder image that the 1.4 produces - especially important if most of your photography happens in dim light 2) the shape of the out-of-focus highlights - hexagons for the 1.7 and octogons for the 1.4

If most of your photos are done at infinity/long distance (landscapes, citscapes, etc.), than the 1.7 is an excellent choice. If you like close-ups, with blurred backgrounds that you want smooth and nice, and are frequently doing photo in dim light, the 1.4 would justify its extra cost.

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Fred - In my own resolution tests (<http://www_cetussoft_com/pentax/resolutn.htm> of three A 50/1.4's, five M 50/1.4's, two A 50/1.7's, and three M 50/1.7's, I found that, in the case of the M versions, the f/1.7 lenses were slightly sharper at wide apertures, but they were virtually the same at all other apertures. However, with the A versions, the reverse turned out to be true - the f/1.4 lenses were slightly sharper wide open, but they were about the same at all other apertures. In these tests, the A lenses showed themselves to be a little sharper than the M lenses, but the difference from M to A was larger between the M and A 50/1.4 lenses than it was between the M and A 1.7's.

While the Pentax 50/1.7 lenses (M, A, F, and FA) all appear to be essentially optically identical to each other (small coatings differences notwithstanding), it appears that the longer series of 50/1.4 lenses does not show quite the same uniformity. While the Super Takumar, Super-Multi-Coated Takumar, SMC Takumar, SMC Pentax ("K"), SMC Pentax-M, SMC Pentax-A, SMC Pentax-F, and SMC Pentax-FA 50/1.4 lenses all have about the same configuration 6 groups of 7 elements (with visually indistinguishable lens diagrams) (ignoring coatings differences over time), Yoshihiko has pointed out previously that the 50/1.4 design underwent a little bit of "tweaking" at the time the A 50/1.4 was being developed. Therefore, there is a slight difference between the M-and-older 50/1.4 and the A-and-newer 50/1.4 lenses, and the higher cost of the newer 50/1.4 lenses does reward with slightly higher resolution as well as a half-stop of higher speed.

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Mike Johnston - I have owned or used the Carl Zeiss Contax 50/1.4, the AF-Nikkor 50/1.4, the Canon EF 50/1.4, the Leica R 50/1.4 (the old one with the 55mm filter thread), a Yashica 50/1.4, The Leica M 50/1.4, and the Voigtlaender Nokton 50/1.5. For all-around image quality in real pictures, the Pentax 50/1.4 is my favorite of them all. The FA 50/1.7 (which I have used) is a very good lens. But the FA 50/1.4 is a great lens.

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> . . . K 50/1.2 vs. the A 50/1.2?

Yoshihiko Takinami - Basically K50/1.2 and A50/1.2 have the same optical design. The only difference is the number of aperture blades; K50/1.2 has eight blades and A50/1.2 has nine blades.

> I suppose A50/1.2 might have better or more advanced coating?

I once have both K50/1.2 and A50/1.2 and tried to compeare the two. I thought differences in the image qualities were so small that I scarcely pointed out which photo was taken by which lens.

The one apparent difference was the description of bright [highlight] in the background. [from a later message . . .] The difference between A50/1.2 and K50/1.2 is the number of aperture blades; A50/1.2 has 9 blades and K50/1.2 has 8 blades. I prefer A50/1.2 to K50/1.2 because the [highlights] in the back-ground is rendered more natural with A50/1.2 than with K50/1.2.

You can see the resolution test results of the two lenses in my web site at <http://www_takinami_com/yoshihiko/photo/>.

They both are very soft wide open because of flare, IMO. I keep A50/1.2 because its image qualities at f/8 or closer are very excellent and very different from those of 50/1.4 or 50/1.7 lenses. I mean I will hardly use A50/1.4 lens wider than f/5.6.

I prefer 50/1.4 or 50/1.7 lens to A50/1.2 when I use one at f/2 or even at f/4.

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> . . . M vs. A?

Yoshihiko - "A" is not optically identical to "M".

The optical design of Pentax 50/1.4 lens was slightly changed mainly for better resolution in corners, I heard, when A50/1.4 was introduced. That means there are two different optics in Pentax 50/1.4 lenses; one is "K" and "M", the other is "A", "F" and "FA". My own experiences support it. My lens resolution test result also seems to prove it . . .

I would prefer "A" to "M" based on my own experiences of the two 50/1.4 optics. Just my opinion.

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Fred - Comparing the M's (and K's) versus the A's, amongst the 50mm lenses:

1. The 2 K f/1.2's were essentially the same as the 1 A f/1.2.
2. The 3 A f/1.4's were distinctly sharper than the 5 M f/1.4's.
3. The 2 A f/1.7's were slightly sharper than the 3 M f/1.7's.
4. The 2 A f/2's were slightly sharper than the 5 M f/2's.

From the data, it seems the biggest difference (improvement), from M (or K) to A, occurred in the 50/1.4's. (. . . Yoshihiko . . . explained previously that Pentax "tweaked" the optics of the 50/1.4 when designing the A version, which would suggest that the A, F, and FA versions should be slightly improved over the M, K, SMC Tak, S-M-C Tak, and S Tak [Model II] versions.)

However, while I've sold off most of these test lenses by now, I've still kept an M 50/1.4 (as well as an A 50/1.4), because using the M lens is simply such a pleasure. "They don't make 'em like this anymore" surely applies to the SMC Pentax-M 50/1.4 lens. The A 50/1.4 is a nice enough lens to use, but the M 50/1.4 is a ~really~ nice lens to use. If I were you, I'd hang onto that M 50/1.4 you already have, even if you do stumble into a good deal on an A 50/1.4.

As for the heavy, bulky 50/1.2 models (both K and A), they tested very much the same as the 50/1.7's overall (which is to say that the 50/1.2's are sharper than some have suggested, in my opinion, because the 50/1.7's are pretty good lenses, with a good reputation). I did keep one K 50/1.2 (to go with my black K2, to be used only occasionally when the K2 is out for "exercise"), and I did keep the A 50/1.2 (strictly as a dedicated dim-light lens, for occasions that call for it). However, the normal lens I take most places with me is either the M or the A 50/1.4.

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> . . . 1.4 vs. 1.7?

Fred - [Based on my tests,] the three A 50/1.4's were sharper than the two A 50/1.7's at most apertures, while the five M 50/1.4's were just slightly sharper than the three M 50/1.7's.

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Greg E. - In March 99 our own Thomas N. Vanveen quoted this from the Auto Extension Tube K manual:

"Lenses not included in the close-up tables are not appropriate for close-up work with extension rings. The 50mm f/1.2 and 50mm f/1.4 lenses are not suitable for close-ups of flat subjects such as documents, but can be used for regular close-ups in which the area of the subject does not reach out to the edges of the picture format."

From this it appears that Pentax is warning you that the 50mm 1.2 and 1.4 lenses don't have as flat a fieldas the f1.7 lenses (f2 lens not mentioned).

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Yoshihiko - Go for FA50/1.7, if you look after visual sharpness even at wide open. Go for FA50/1.4, if you look after rich tonal color rendition.

takumar的用料是pentax中最足的，在用料方面的确是九斤老太所言：一代比一代差。

以前用过smc takumar50/1.4,前镜组有问题，后来出掉了，但对1.4的情节始终弥灭不掉。入宾得以来，大光圈标头也玩得不少了，从最初的理光50/1.7、确山能50/1.7、宾得A50/2到pentacon 50/1.8、宾得A50/1.7、helios 44M5 58/2、梅耶版pentacon 50/1.8。但这些标头始终找不到1.4大光圈下特有的虚幻景深效果。有时候也纳闷，1.4和1.8也不过差半档光圈而已，为什么会这样？

也可能是心理作用，前段时间刚卖掉那只成色极好、成像也很好的假梅耶50/1.8，又买了一只M50/1.4回来，还在路上呢

虽然PENTAX 67II资深的话令很多宾友伤心，不过大体属实!TAKUMAR还真的是最初的AUTO TAKUMAR 做工更精致一些!当然到S-M-C TAKUMAR仍然尚算经典，但SMC TAKUMAR时已经简化了。前几天才出手一个SMC TAKUMAR 55/1.8.今天却入手SUPER TAKUMAR 50/1.4，现在正在路上。对我而言，手动镜头做工和精致也是很重要的。

[091156 编辑于 2011-03-08 16:38]

还有就是F

A50/1.7廉价质量好！

有放射性是因为用了含有“钴”的光学玻璃，不是镧系。俄头的小微距也用了镧系玻璃，她怎么不变黄呀？ 好好学学化学再来吧。
M42的头可以使用 A 档，机器进行适时测光。但是注意机器是自动以 50mm 1.4 为标准测光的。
也就是说，最大为 1.4 光圈的镜头可以准确测光， 但2.0就要 +1EV， 2.8就+2EV。一般机器就是正负2档曝光补偿，所以小于2.8 的就不要用 A 档了，因为用了曝光补偿也会欠曝。还是老老实实的用 M 算了。

只要有胶合镜片的就有潜在的开胶的可能，可不能“之说”啊。

用A吧、只有1000左右吧。。。

说实话，一般人用来拍照片，还真分不出一二三。
拣个便宜的、成色新的开用吧。

用smc50/1.4，这支成像非常好，现在一直用他给宝宝拍照。

俺觉得takumar转接后用A档挺方便的啊。只不过光圈用镜头光圈环控制吧，和A档差不多？？
只不过有时候测光不太准。我有只smc takumar55 1.8。用起来挺爽的，对焦没想象的困难。就是小光圈时测光不太准，而且白平衡也有问题。。还有就是小光圈时取景很暗。。这点不爽。

K

没必要往什么德味上靠，我几十年所玩过的日本头，哪只也都别提什么德味，别提什么层次色彩暗部响应过度空气感油润感厚味的，日本头就是日本头，没有谁家脱离了日本头的水平，只不过宾得个别头表现的确很卓越，有些脱胎换骨的味道，代表头FA43等公主，还有各家著名的七种武器，都算是佼佼者，但是也别提什么德味。而且德味未必就好，还要看拍摄题材和表达需要。

论色彩，反而更多人认为A头色彩更容易让人接受和喜欢。

[至尊宝 编辑于 2010-08-11 17:45]

M，颜色更润，更有德味。