older Prime vs newer Zoom

If you just want an old manual prime to play with then look for either of the Pentax 28mm f3.5s, both are very handy performers and can be had for around the £50 mark if you keep your eyes open and are ready to pounce.

To be honest... If you have the Tamron 17-50 and you really want to go 'prime' too then it's probably worth waiting and saving for one of the LTD lenses...

I pretty much just use the Tamron and the FA50 which complement each other nicely...

I'm trying to my LBA on hold til I can afford the DA35mm macro LTD (and then the Tamron 90mm macro) which will also complement my kit...

I was amazed by the IQ of the smc Pentax-K and Pentax-M 200mm f4, for around £60.00 they are well worth a look. and you can sell them on later for the same price.

I think this is a rather futile discussion...

when you consider that the rather elderly F35-70 and F50 1.7 are held in high esteem.. and the F50 f1.7 is preferred over the FA 50 f1.4 for instance (I replaced the F with the FA, now I have reacquired the F:wink

In my case my equipment is rather limited by the operator

I think I should look for an excuse to take out the FA*85 to see how it compares with the DA*60-250 when it's returned from Pentax.

Hi Andrew, they look OK, but without comparing two shots of the same thing it's a bit difficult to judge. Possibly the Chinon is better close up than at a distance. Grass is also not that good to judge IQ by. There could be different models but most budget lenses tend to be the same design with possibly an external re-vamp. Below are some test shots that I did. I'm keeping the lens for close up work.

This is the Pentax 18-55mm Mk2 Kit Lens (LHS) -v- Chinon 28mm f/2.8 (RHS)

Both at f/8 at 1/200th sec.
Pentax K-5 200ISO
No PP straight from camera JPG's
Camera on tripod Square to bridge.

1:1 (100%) Centre of frame Compare captured by a screen grab at 800 wide.




1:1 (100%) RHS of frame Compare captured by a screen grab at 800 wide.




The Chinon is quite nice close up for things like flowers and has
a pleasant bokeh and 3D look.




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Lots of positive opinions on the Tamron 17-50. Is it better than the Pentax 16-45? I thought about both and bought the Pentax.

It might be futile if you have a shelf of * lenses.

I'm just on the casual hunt for a 24-30mm range lens but wondering if its worth it over the 17-50.

By the sounds of it. not.

My capsule lens line up looks ok and a 24mm old prime probably won't give me any more image quality.
l

My idea of a futile discussion is going into the Bugatti Veyron Forum and asking
how I repair a leak in the bottom hose of my radiator

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Agreed - but my intention was simply to illustrate that my copy of the Chinon isn't terminally soft in the corners and hence unusable for landscapes. It was just a crop from a "snap" that happened to have material with fine detail in a corner.

It's difficult to draw conclusions about your bridge photos. The left and right screen captures are not of exactly the same part of the frame. Also, the colour is obviously different. The light has changed a bit between shots - the shadows of rivets are more pronounced on the RH centre crop. As an aside, I've never seen CA on a kit lens before (I assume the left shots are the kit) near the centre of a frame.

I must do some more comparisons,some time soon, between the kit lens and the three cheapie primes I have in the same focal range (Sigma 24, Chinon 28, Rikenon 50). If the kit lens really is as sharp as the primes, I can do some considerable decluttering of my kit bag(s). At the moment, though, I'm convinced that it isn't, though my testing has been mostly at f5.6 and is not as rigorous as I would like.


Andrew

I didn't pay much attention to the centre of frame shots, I was only really illustrating the edge performance, which was the same on both sides of the frame so no de-centering problem. They are the actual true centres of each frame, but I should have aligned them better. I've also noticed that the Kit Lens shot has some slight camera shake in it.

There's a lot of extra Blue in the Chinon shot. The camera
was set to Daylight.

The Pentax_A 28mm f/2.8 wasn't much better than the Chinon.

The Sigma II 28mm f/2.8 was poor.

I'll have to dig out my Kiron 28-105mm and see how that compares

I spent much of this morning fiddling with lenses, a K200D, tripod, cable release, Pentax flash and so on to start the process of comparing the three primes I mentioned above with the kit lens. The testing process is limited to comparing the resolution of the lenses using the Amateur Photographer lens test chart and says nothing about colour rendering. Rather than hijack this thread, I'll go into the detail of exactly what I did and show crops of the test charts in another, so that you can judge for yourself whether the results are meaningful or a load of tosh.

I am pretty confident that, for the samples in my possession, these summaries give a reasonable indication of the differences between the lenses when used at f5.6.

Summarising ........

1) I now agree with Algernon that the Sigma 24mm f2.8 Superwide II is poor at the edges and especially in corners. It is, though, obviously sharper than the 18-55mm ALII kit lens in the middle of the frame.

2) I completely disagree with Algernon about the Chinon 28mm f2.8. It is at least as sharp in mid-frame as the Sigma and massively better at edges and in the corners. It is sharper than the kit lens everywhere.

3) The XR Rikenon 50mm f1.7 is much sharper than the kit lens everywhere. Overall, it is by far the sharpest lens on test. It is about as sharp in the extreme corners as any of the other lenses in mid-frame.

The bottom line here, is that if you want a cheapie sub £25 prime lens then you would do well to look at the Chinon 28mm and the XR Rikenon 50mm f1.7. Beware though, that there are several variants of both lenses and some might be better than others. You also risk varying results due to sample differences.

Andrew

Interesting Andrew

It was the 28mm Sigma that I mentioned, nice to know that the 24mm is similar.

There can be a difference how a lens works close up and how it works at say 50m.

The 50mm Rikenon I compared before was identical to the Pentax A 50mm f/1.7.

It didn't perform that good in an AP test of all the 50mm lenses.
The best was actually a 50mm CZ Jena f/1.4, but they go for £300 now.

If you want a lens with character the 55mm lenses are better.

I haven't seen the AP test of 50mm lenses - is that available online? The "tests" I've done speak only to the resolution of the lens and not to any other measure of goodness.

As an aside, I do appreciate that lenses may perform a little differently close up and at infinity - but I doubt that the Sigma 24mm is going to sharpen up, in the corners, substantially on distant subjects. The difference is gross. Having said that, I've taken hundreds of photos with it and not previously noticed serious corner softness - perhaps because it's rare that anything in corners is the main subject of the photo, so maybe some were soft but it didn't seem to matter. I suspect, though, that it's simply that photos of test charts - limited though they may be - are more discriminating than just taking photos of {whatever} if your primary purpose is to compare lens resolution.

Andrew

I have the Tamron 17-50 as a kit lens and at f2.8 it performed brilliantly with my K-x. I had also Pentax-A 28/2.8 and could not say it outperformed the Tamron in any way (so I sold it).

As far as I found, the mkII kit lens was close if not equal to the 16-45.

The 17-50 when used correctly is sharper and give you a bit more low light.