smc 50mm

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Link Posted 01/01/2010 - 11:15
Hello all, I'm after a 50mm lens to fill out the camera bag. Preferably an older A series lens, which will fit the minimalist budget. The f1.2 is rare, and I'd never be able to get the focus plane right anyway, but the f1.4 and f1.7 are more common. I'm leaning towards the f1.4, simply because it's so fast, but is there much difference in real terms betweenthe two? Any thoughts please?
Pentax K7, Sigma 17-70 f2.8-4.5, Sigma 70-200 f2.8 APO EX, Sigma 70-300 APO, Sigma 1.4x TC, Vivitar 2x TC. Takumar 135mm f2.5, SMC Pentax A 50mm 1:1.7, SMC Pentax -M 1:4 200mm, Pentax X70


Link Posted 01/01/2010 - 11:23
The f1.4 has great quality that is much admired on the forum, but is quite rare/expensive - likely over £100 in the UK. Out of focus rendition is excellent. The f1.7 version is very similar, arguably sharper wide open and has a flatter focusing field and better close focusing. Price in the UK is perhaps £50 or maybe less.


Link Posted 01/01/2010 - 11:30
Go for the f1.7.

I have both A and M versions, all of which give excellent results.

Sample from my one of my SMC-A 50mm F1.7 wide open here

Cheers, HG

K110+DA40, K200+DA35, K3 and a bag of lenses, bodies and other bits.

Mustn't forget the Zenits, or folders, or...

I've some gallerieshere CLICKY LINK! and my PPG entries.


Link Posted 01/01/2010 - 11:32
The 1.7 has a flatter focus plane, so you can more often get sharper images towards the edges of the frame at large apertures. It's also lighter and a lot cheaper.

On the other hand, the 1.4 is possibly sharper at medium apertures.

(I have one of each, but haven't compared them scientifically, so I'm just quoting common knowledge).


Link Posted 01/01/2010 - 11:59
You can pretty safely assume that all the Pentax 50mm lenses will give similar results from f8 onwards. At wider apertures the different characteristics will begin to show.

The f1.7 and f2 designs are the best for the sheer ability to (optically) abuse them by adding close up devices and using bellows, extension tubes and so on.

The f1.4 has more contrast as suits its reportage and low light functions. It does have lower resolution so this is not for you if copying or ultra fine detail is what you need.

The f1.2 is brilliant for those who need it, and wonderful for those who desire it.

In general terms, if you are using the images for the web and maybe up to A4 prints you'll be hard pressed to say which of the lenses is better.

Preferably use A series or later on digital for the covenience in operation that it brings. Having said that, I'm offering an M series f1.7 on eBay now, currently at £10, which is in brilliant condition.
Best regards, John


Link Posted 01/01/2010 - 12:04
I'd go for the f1.7, with a view to buying an f1.4 later if you see one for a good price. Manual focus lens prices seem to have got ridiculous of late, especially A series primes.

Bear in mind that if you end up with both and decide to sell one you won't lose anything financially. Prices are either stable or rising.

Shooting the Welsh Wilderness with K-m, KX, MX, ME Super and assorted lenses.


Link Posted 01/01/2010 - 12:09
Just bought the f1.7 from another forum member, just waiting for it to arrive.
I asked nearly the same question and followed the advice given by various members.

Will post some shots on the forum at some stage.



“Nobody made a greater mistake than he who did nothing because he could do only a little.”
Edmund Burke (1729 – 1797)


Link Posted 01/01/2010 - 19:26
I recently bought the A f1.7 lens and i am really struggling to get to grips with it, many of my photos seems to be out of focus. I'm a bit of a novice, and don't understand techy talk, but I would like to know what this lens is good for-what's the best way to use it? I bought it for portraits but find you need to be to up close and personal...?


Link Posted 01/01/2010 - 19:54
I've actually been using mine for landscapes - it's quite a narrow field of view compared to the more usual wide angle lenses but if you pick your composition carefully then it works pretty well. I find it very handy for making structures fill the frame rather than ending up with huge amounts of greenery with a building in there somewhere! It's also handy for looking through gaps in greenery (say trees between you and the lake you want to shoot) without catching branches in the frame.

Manual focus isn't easy on DSLRs as they usually just have a plain glass focussing screen (as opposed to the split screen on older film SLRs where you focus until a line on the subject is smooth). You can buy replacement split screens but you have to spend a fair bit of money to get one worth having. I haven't bothered as I seem to cope well enough without one.

The in focus beep/green light in the viewfinder will both work with manual focus, which may help.

Shooting the Welsh Wilderness with K-m, KX, MX, ME Super and assorted lenses.
Last Edited by Dangermouse on 01/01/2010 - 19:55


Link Posted 01/01/2010 - 22:37
Thanks Matt, I've been using the focus beep, and today took just the type of photos through trees you mention-but still not really sharp images-


Link Posted 01/01/2010 - 23:12
pamt wrote:
I recently bought the A f1.7 lens and i am really struggling to get to grips with it, many of my photos seems to be out of focus. I'm a bit of a novice, and don't understand techy talk, but I would like to know what this lens is good for-what's the best way to use it? I bought it for portraits but find you need to be to up close and personal...?

It's good for portraits when you don't mind being up close and personal! Also good for still life and product pictures.

Focus by simply judging what the image looks like through the viewfinder, or by the green hexagon indicator in the viewfinder, or with Catch-in Focus aka focus trap. See the camera manual for the latter.

A 70, 85 or 90mm lens would be better for portraits from more of a distance. A good one can be expensive, though.


Link Posted 01/01/2010 - 23:18
Pamt, I have a 50mm 1.4 M version and it took some time to 'get to know it', especially at f1.4 and f2. The depth of field can be so shallow that even when the green light gives you focus confirmation, it's still a little off. Or, for xample, you focus on someone's faces, and it gives you focus confirmation because the tip of the nose is in focus, but with the shallow field the rest of the face will already be out of focus. This effect is the stronger the closer the subject is... for certain shots the in focus field is only a few centimeters deep.

Where possible, I tend to take a few shots with slightly varied focus around the confirmed point.


Link Posted 01/01/2010 - 23:20
Don't get hung up on the speed. The f1.7 is not much slower than the f1.4. In fact the difference is exactly half a stop. Hardly noticable in real life.
No man is worth his salt, who has not been banned from at least one Forum, and two Flickr groups.



Link Posted 02/01/2010 - 08:10
pamt wrote:
I've been using the focus beep . . .

The focus beep is not a true indication that the lens is actually focussed. The only correct indication that a lens is focussed is the green hexagon in the viewfinder.

The beep simply means that it has chosen a focus point, also indicated by the red square in the viewfinder.

My suggestions:-

1: Ensure the dioptre adjustment is correct by removing the lens, aim the camera at a bright light source (NOT the sun) and adjust the dioptre until the framing lines in the viewfinder are sharp. Re-fit the lens.

2: Choose the centre only focus point on the focus selector switch on the rear of the camera.

3: Set the camera & lens on a tripod and take some shots making sure that when you make the exposure, the green hexagon is visible in the viewfinder. If you don't have a tripod, use some other means to ensure the camera does not move at all when you make the exposure and use a minimum shutter speed of 1/250th for this exercise.

4: Make several exposures using different apertures. You'll get the sharpest results somewhere between f8 and f16.

Let us know how you get on.
Peter E Smith

My flickr Photostream
Last Edited by Mannesty on 02/01/2010 - 08:11


Link Posted 02/01/2010 - 09:45
You should also check that your viewfinder diopter is set correctly when you are manual focusing.

Edit: Oops sorry Pete, should have read your post first.
Pentax Lenses:|DA12-24/f4 ED AL|DA35Ltd Macro|FA31Ltd|FA77Ltd|FA50/1.4|F70-210|FA20-35 f4/AL|A*200/f4 Macro ED|A50/1.7|A50 Macro f2.8|1.7xAF adapter|
Voigtlander|125/f2.5SL Macro APO Lanthar|
Sigma Lenses:|EX DG 100-300 f4|2X & 1.4X TC|
Flashes:|AF540FGZx2|RingFlash AF160FC|
Last Edited by Clarky on 02/01/2010 - 09:47
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