rparmar

Joined: 23rd February 2008

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rparmar
A while ago I tried about six of the best print shops and compared the results. Loxley won and were not the most expensive.

For mediocre printing at bargain basement prices, I use whatever local place has a machine.

Comment by rparmar posted on Recommended printers? at 04/03/2013 - 21:37

rparmar
johnriley wrote:
I'm not sure you read my statement properly rparmer - what I said was that my favourite was the 43mm, so how you contend that it isn't true?
Where did I say it was untrue that your favourite was the FA43? I quoted the entire statement to comment on the second clause. This is obvious from the fact that all my statements are about the second clause. How could you possibly think I was arguing with what your favourite might be? Especially as I share this opinion! Truly bizarre.

johnriley wrote:
I don't need to check out the EPZ published reports, mainly because I wrote them....
You seem to think that because I am replying to a post you wrote I am writing only to you. Not so, I am writing to everyone who may be reading this thread. Otherwise I would send you the info in a private message. Not all the readers here will have the same facts to hand as yourself. I would have thought you'd have been happy to have your own article referenced (it's here), but instead you use this as yet another reason to pick a fight with me. How very odd.

In any case, if you compare the MTF50 charts for the FA43 and FA77 (something that should be dead easy for you to do since you are so familiar with the ePhotoZine articles) you will see that the FA43 has higher peak values both at f/2 and at its best aperture. It even has higher weighted values at f/2, despite its notoriety for poor corners. Apart from this, the FA43 has highest MTF20 in the centre, across apertures. And less tendency to purple fringing, though CA is high.

Thus your statement "despite its technical performance on paper being the lowest" appears to be false, based on the very tests you are familiar with. The FA77 actually has lower performance. That is the claim I made, which I didn't think needed this sort of elaboration (since anyone can compare the values they find important for themselves).

The only other possibility is that you are now using "performance" in a way others do not. I find this unlikely, since in the article in question the section headed "performance" does indeed examine, among other things, these MTF charts I am using as evidence.

And no, this argument does not imply that I think these differences are significant. Nor does it imply that I think one should judge lenses based on lab bench tests. Nor does it have any immediate bearing on the FA31, a lens I do not own and so will not compare in this fashion. Others may wish to do so.

Comment by rparmar posted on FA 31 Limited - why is it so good? at 24/02/2013 - 17:24

rparmar
johnriley wrote:
Nonetheless some lenses perform better than others in a technical sense, but it all depends on what the desired effect is as to whether a lens is "better".
I agree that one cannot judge fitness to task until one knows what the goals are. However, most people underestimate what can be read from specifications. Unfortunately Pentax does not publish proper MTF 5, 20 and 40 graphs (unlike Leica, for example) so we are left in the dark or reliant on third-party tests. These are also often incomplete and impossible to compare across labs.

With proper graphs we can even make statements about bokeh quality, etc. Erwin Puts' documents for Leica are make fascinating reading in this regard. Though specs may not say everything about how the lens renders, they do say a lot more than most casual photographers realise.

This reality doesn't accord with the ideologies of individuality and subjectivity that many ascribe to. People would rather think it's all about them! (Lens designers know otherwise. After all, contemporary lenses are designed from start to finish on the computer.)

johnriley wrote:
Of the three FA Limited lenses though, my favourite is still the 43mm, despite its technical performance on paper being the lowest.
I made a study of this matter some time ago and must say this statement is not true. The FA31 has the same rather poor distortion and CA qualities of the FA43. And the FA43 has higher peak MTF 50 than either of its brethren. All have poor purple fringing, but especially the FA77.

So my conclusion is the opposite of yours: the FA43 has the best specs on paper of the three.

I don't have references to hand but check out ePhotoZine and PhotoZone, both of whom have published test results.

Comment by rparmar posted on FA 31 Limited - why is it so good? at 24/02/2013 - 13:15

rparmar
wvbarnes wrote:
No mention of the crop factor.
It would do nothing but confuse the beginners this is obviously targeting. But your point is taken, since they define normal as starting with the 35mm, instead of at 28mm.

Of course here is no Pentax 28mm lens. I guess they wouldn't want to draw attention to this glaring omission.

Comment by rparmar posted on Chosing a Lens at 19/02/2013 - 21:08

rparmar
A good introductory video for beginners. Glad Pentax is finally deciding to educate people. Primes were emphasised, which is interesting.

I'll note that the 35mm prime is included in both the normal and the wide angle categories. Right after the narrator said that wide angle is less than 35mm. Well, that's my nit-pick for the day!

Comment by rparmar posted on Chosing a Lens at 19/02/2013 - 02:41

rparmar
People are really confused about equivalence. If you want to take the same photo from the same perspective with two different sensor sizes you will need to change the focal length to get the same FOV. That's why we talk about "equivalent field of view".

Also, arguments about how handy the Q is because it can be in your pocket are beside the point. I too find a smaller camera handy, which is why I shoot with an Olympus PEN. This has nothing to do with which sensor is better.

Comment by rparmar posted on Merits of APS sensor at 05/02/2013 - 13:10

rparmar
Me too, but I use a rename programme I wrote ages ago. I can set up templates and easily switch between them. I prefix all the photos numbers to indicate the camera used and let the sequences move up for each one.

I do a hard format of each card if I switch cameras. So far this has worked without odd numeric jumps.

Comment by rparmar posted on Oh Bugger... at 05/02/2013 - 00:26

rparmar
McGregNi wrote:
As a photographer who only infrequently makes use of high iso settings (400 +), I am curious to know whether upgrading to a newer model (which boasts of improved high iso performance) would also offer any additional IQ at the low settings - I mean, would the sensor give more IQ to images shot at ISO 100 with the camera on a tripod?

I don't see sensor performance under these conditions referred to in discussions (or advertising) about new models.
You have hit one of my pet peeves.

My K20D produces better low ISO images than the subsequent couple of models I have used (K-x, K-7). I haven't used the K-5 or K-30 but there is absolutely no indication that this has changed.

In fact base ISO is creeping up. Instead, give me a base ISO 50 camera with zero noise. Yeah, it can go to IS1600 if you like, but leave the stratospheric numbers to the marketing dept.

Comment by rparmar posted on 24mp APS-C? at 05/02/2013 - 00:23

rparmar
ronniemac wrote:
Comments and images now lead me to believe that rather than upgrade to a K-5 IIs, for image clarity, I should buy either a Limited or * Lens. (and for that Mondrian effect - carry on using the kit lenses)

In other words, for high resolution camera I should spend my pennies(!) on quality lenses, and keep my K-5. Simple! Your photographs say it all Mille19
Exactly so. Incremental improvements in sensor technology and image pipelines will continue, though we seem to be at a plateau. Or even slipping backwards in the quest for high ISO... where is the quest for the best low ISO image?

It is easy for manufacturers like Pentax to make incremental improvements and sell us a new camera. But for some reason it seems almost impossible for them to produce any new stellar lenses. Innovation has halted in exactly the field where it is most needed.

The best, most distinctive, lenses Pentax ever produced are the FA Limiteds... pretty old tech by today's standards. I have no doubt that with today's CAD they could make them even better (APO versions ), but the will is not there.

In the meantime buy the FA Limiteds to see how good your images can look. If that is your priority, this would be a much better investment than a new camera.

Comment by rparmar posted on JR K5 IIs review at 05/02/2013 - 00:17

rparmar
sussexwolf wrote:
The small sensor's larger depth of field is an advantage for some things (eg Landscapes) But a disadavntage for others (eg portraits.)
This makes no sense. You can always stop down a lens to get more DOF. But you cannot do the opposite.

Besides, stopping down with a smaller sensor runs into the diffraction limit sooner.

Plus a smaller sensor limits field of view.

That's three strikes against, without even getting into arguments regarding resolution and noise -- let's not!

Sorry, but there are no photographic advantages to a smaller sensor. If you think there are, remember you can simply crop an image made on a large sensor to get the same net effect.

That said, I am happy with an MFT sensor, and would be happy with APS-C if Pentax would ever produce a competitive mirrorless model. Because for me the practical advantages of portability outweigh the photographic advantages of the larger sensor. Plus, I can afford the gear.

Comment by rparmar posted on Merits of APS sensor at 04/02/2013 - 23:55

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