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Can we use a film camera lens (conventional) on a digital SLR where a telecentric lens is optimal (current)

McGregNi
Posted 02/02/2015 - 19:15 Link
Sure Gary, but I'm thinking when you say modern lenses for press work, you mean speed and accuracy, you're not really worrying about the angles that light rays hit the sensor are you?
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Daronl
Posted 02/02/2015 - 22:06 Link
In answer to Mr McGregor's question, I doubt a pro would not be worried about the technical performance of a modern lens because a pro or enthusiast would likely not invest in a lens that would be subject to performance and quality limitations as regards the final picture quality.

Slightly rephrasing his question to make it more aligned to the discussion ; would a pro be concerned about the potential limitations of having no alternative but to use an older lower spec conventional lens if for some reason his new pro spec. Lens was not available for a demanding and prestigious shoot.

Of course any pro would be concerned, particularly if the shots were to be the subject of of professional scrutiny by a client ahead of them being used for, published materials, big enlargements, big crops or were to be put up as large display prints.

No one would be sitting there thinking specifically about convergence angles but they would be concerned about the performance limitations of such a lens when measured against the state of the art pro'spec lens that was the lens purchased for such a professional shoot.

It is not necessary to understand the science but the technical evolution of lenses is based on the evolving technological developments of photographic equipment.

When anyone, whether a pro, enthusiast or hobbyist photographer spend their hard earned shekels on a beautiful new K3 it is not ideal to then stick a twenty five year old lens on it.

I have several twenty five year old lenses ( in fact I have a some that are older) , that were the ultimate performers of their day and they still turn out respectable results on twenty year old film cameras ; they certainly would not bring out the best in a K3 or indeed a state of the art film camera.

So the whole point of the principle question of this thread is fundamental in that last statement.

To ask a pro photographer if he is worried about about convergence angles when he is doing his job is not a serious consideration, and clearly does not address the discussion.

In any technical product we to have pay due respect to the evolution of the technology; would we replace the engine in a new BMW with a a thirty year old well used engine even if it is perfect working order

Would the owner be worried about the different combustion pressures or cylinder block metallurgy if the car wasn't able to perform as it it did with the latest motor, no only the fact that the engine didn't do justice to the rest of the technology.

As I said above, we don't need to understand the science but we do need to pay due respect to it before we mix different generations of technology between interdependent components that define the end result, the picture.
Daronl
cabstar
Posted 02/02/2015 - 22:20 Link
McGregNi wrote:
Sure Gary, but I'm thinking when you say modern lenses for press work, you mean speed and accuracy, you're not really worrying about the angles that light rays hit the sensor are you?

The majority of the latest lenses apart from vibration controls and focus speeds and coatings I think due to computer design and better manufacturing processes are typically now at their technological peak. Take the wide angle lenses the Nikon 14-24mm is considered one of the worlds greatest lenses and that's purely down to better design, knowledge and manufacturing which just wasn't available ten years ago never mind twenty or thiry years ago.

With the increase in sensor resolution older lenses are going to be made even more obsolete and the choice of the skint and the artist photographer.
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johnha
Posted 02/02/2015 - 22:54 Link
I've resisted posting to this thread because my opinions are quite blunt - I don't give a damn. If a lens doesn't give me the results I want I stop using it, doesn't matter if it's old or new. Newer doesn't mean better - just ask the EOS shooters who'll pay more for a 40yr old Super-Tak than the 'new' EF mount equivalent, despite all the interface problems they create.

There are so many other more important variables to get 'spot on', insignificant differences in IQ are, well, insignificant...
McGregNi
Posted 03/02/2015 - 08:20 Link
A working professional will have different requirements to enthusiasts for many situations ... and different budgets as well. I can well see that the latest coatings and AF technologies will be important to those who need the fastest and most reliable performance, particularly in more dynamic people oriented work.

But really, when I asked about whether light convergence was a worry, I mean that the effects of it (with older lenses) will not be the primary concern or interest to anyone when choosing and comparing. We all look at the overall results, resolution and sharpness being one of the main factors, as well as 'contrast' matters and physical handling / weight issues, and autofocus performance. Those are the things you see discussed endlessly on forum threads about lenses ... including professionals.

Daroni, you speak a lot about image quality matters in relation to old lenses, but you are not very specific about what exactly are the problems you worry about. I've mentioned purple fringing and contrast in backlighting with my 28mm .... but these are limited problems in limited situations. The vast majority of CA problems I've encountered, both with old film-era glass and modern ones, can be dealt with successfully with minimal PP effort ... or they're insignificant at any normal viewing size so not worth bothering about.

If its not these small matters that you are making such a fuss about, what exactly is it? Can you show comparative examples of old and new glass with the same scene? Most of us love and appreciate the qualities of the old lenses we treasure, both for the high amounts of IQ and bang per buck they deliver.

I accept Gary's point above from the view of a professional who has to get through hundreds of shots every week maybe, and can't be worrying about processing and removing any small abberations. But I suspect that for most pros the main concerns will be for reliability, handling, sharpness, AF performance ... much like the rest of us .... and they won't care what era the lens is from so long as it delivers those things as needed.
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Daronl
Posted 03/02/2015 - 13:17 Link
Bearing in mind the commentary above from Mr McGregor;

Firstly let me underline one thing, the purpose of raising a topic on such a forum is to share / gain knowledge and experience - not to "make a fuss" as you put it Nigel.

My philosophy is always respect and pay attention to the science. which is what I am sharing in this topic in a very simplistic way - not making a fuss

As regards the thread of the topic, it was raised because seemingly it is increasingly accepted that film lenses (sometimes quite older lenses) can be used on state of the art high resolution DSLR's

I have said repeatedly in some cases they can but in some cases they shouldn't be used as they impair final IQ and most definitely don't get the bess from the camera

What is curious to me about your commentary is that on this same forum lenses are reviewed and CA, fringing and sharpness are principle evaluation points that influence the final assessment of the lens because to varying degrees affect IQ, in some case negligibly in other critical applications, seriously.

Additionally on an almost daily daily basis we see queries as to the comparative image quality of various lenses and the very well understood CAs ,fringing and associated defect are commented on.

Take a look at the reviews on the excellent Pentax HD converter and likely you will see references to such defects all be it in the case of this converter they are at a better than acceptable

For clarification the physics is well known image sensors require collimated telecentric light impingement where as film lenses are based on converging ray impingement.

Wide angle film lenses are most prone to the IQ defects mentioned when used on a Digital camera and are of most concerned telephoto film lenses are are less prone to the problem but are not ideal

In the case of serious enthusiasts, people involved in technical photographic applications and Pros in general, the fundamental principle is to minimise any potential image defects that are associated with the quality of lenses and to ensure the lenses enable the performance of the camera to be optimised and not impaired by the lens quality.

All mountable lens camera combinations will enable a photo to be taken, whether it would be at competition, exhibition or saleable standard is another thing.

If a photographer does not need to concern themselves with such IQ defects then top class film lenses are an option even though there might not be a need to buy a state of the art body if that is the case

To most hobbyist a budget camera and budget modern lens will surpass IQ requirements and the defect mentioned above won't bother them or the viewer of the final image .

Yet still people make choices and will buy or dismiss a lens based on expert reviews and technical evaluation.

All people with a camera in their hands concentrate on getting the best image hence we aspire to buy the best kit we can afford, so then all we have to struggle with is Feild conditions which are ever changing

As regards the comment that I have not been specific I think you need to re read what I and others have written here it relates to defects associated with the way light rays impinge on the film plane or image sensors

These types of defects ie. Chromatic Aberrations in the form of spurious highlights, halos, fringing and the like, are well documented understood as defects, and examples can be seen on many lens reviews; you surely must know what they are of course unless you are the one photographer who has never suffered with them or conversely ignore them or in fact don't no what they are.

my final comment on the subject highlights another aspect that will increasingly render conventional lenses "challenged" because todays sensors enable enormous crops and enlargements which means we also enlarge the defects too.

Large format film lenses apart, 35 mm lenses were rarely pushed further to 14x11 prints.

A K3 will produce images much larger and if the lens is older technology and in particular not tele-centric the aberrations and image will be much more prevalent.

When you put a 1.4 x converter on your DA* 300 which is a superb optic, mounted on a K3; take a shot of a static object then put it on screen, select an area and enlarge the image to "actual pixel size" and copy it.

Then do the same without the converter and you will see the negative affect of the converter.

However providing you are not intending to make display images/prints and limit yourself to a laptop screen, mobile phone or 7 x5 print you won't notice it ; AND THAT IS FINE.

However as sensor size and resolution gets bigger and better we need to pay attention to the increasing limitations of older lenses, particularly wide angles with their more acute convergence angles

I come from the professional era of Kodachrome 64 and very slow film, sometimes very low shutter speeds for ultimate quality when like today lens and camera design and spec' was aimed at ultimate quality .

Today being able to use high ISO, shake reduction and other technologies is incredible but the downside is it can seriously expose the limitations of older lenses.

All I know is this; some of the images I have had published in the distant past would not make it today and on a recent indoor sports shoot it became clear to me that
even 7 or 8 years ago I simply could not have taken some of the pictures I took that day; because the lens technology was not available and Iso 800 film would have produced extremely poor quality

A) I would have needed a flash ( not permitted at courtside)
B) I couldn't have focussed to dark
C) I couldn't have hand held
Aperture size limitations
Lens quality at wide open aperture not good enough
Maximum ISO limited to 400 to avoid grain etc

Etc, etc

If the photo application (IQ) doesn't warrant concern about the typical defects mentioned throughout the thread then consider them and make sure you minimise them by using the best of the film lenses; but bear in mind you might not need to buy a K3 .

I have said all I can say based on my experience as a working photographer of many years but will always read other peoples opinions in the hope I continue learning, I certainly align with some of the comments from Mr Stafford (CABSTAR) and Mr Halliwell9 (Johnha) above

But frankly there is very little chance, if any that I would use an old conventional lens on a K3 or a 6D instead of a DA* star or a Canon EF if I am on a commission - IT WOULD HAVE NO ADVANTAGE TO DO SO

My philosophy is always respect and pay attention to the science.

Regard













Sent from my iPhone=
McGregNi wrote:
A working professional will have different requirements to enthusiasts for many situations ... and different budgets as well. I can well see that the latest coatings and AF technologies will be important to those who need the fastest and most reliable performance, particularly in more dynamic people oriented work.

But really, when I asked about whether light convergence was a worry, I mean that the effects of it (with older lenses) will not be the primary concern or interest to anyone when choosing and comparing. We all look at the overall results, resolution and sharpness being one of the main factors, as well as 'contrast' matters and physical handling / weight issues, and autofocus performance. Those are the things you see discussed endlessly on forum threads about lenses ... including professionals.

Daroni, you speak a lot about image quality matters in relation to old lenses, but you are not very specific about what exactly are the problems you worry about. I've mentioned purple fringing and contrast in backlighting with my 28mm .... but these are limited problems in limited situations. The vast majority of CA problems I've encountered, both with old film-era glass and modern ones, can be dealt with successfully with minimal PP effort ... or they're insignificant at any normal viewing size so not worth bothering about.

If its not these small matters that you are making such a fuss about, what exactly is it? Can you show comparative examples of old and new glass with the same scene? Most of us love and appreciate the qualities of the old lenses we treasure, both for the high amounts of IQ and bang per buck they deliver.

I accept Gary's point above from the view of a professional who has to get through hundreds of shots every week maybe, and can't be worrying about processing and removing any small abberations. But I suspect that for most pros the main concerns will be for reliability, handling, sharpness, AF performance ... much like the rest of us .... and they won't care what era the lens is from so long as it delivers those things as needed.

Daronl
willyolly
Posted 03/02/2015 - 13:52 Link
Thanks to Daroni for making some interesting and valid points. However I must take issue with his assertion that "35mm lenses were rarely pushed further to 14x11 prints". Many photographers, both amatuer and professional have produced prints (mainly B&W in my own case) upto 16x20 and above from 35mm for both competition/exhibition and commercial use.
McGregNi
Posted 03/02/2015 - 14:16 Link
Would the limiting factor with film era prints not have been more the film itself, rather than lens design technicalities? I do accept that very high resolution and large digital sensors might be unforgiving of lower quality old glass. Clearly we all have to choose carefully. I myself have raised many times my own hopes for using my modest collection of old (and new) FF lenses oh a future Pentax body ... But I realise this may be a forlorn hope ..(sure is sounding more and more like it now!

But the reality is, I won't be able to afford the camera PLUS a new collection of FF modern digital optimised lenses, not at once certainly. So I'll have to make the most of what I've got. What I've got packs a lot of punch for the money .. The question is, would it be better to use the old glass for all its great qualities on a FF body and deal with the aberrations where needed, or keep limiting their use to a much lesser sensor like the K7?
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johnriley
Posted 03/02/2015 - 14:39 Link
Who knows at this point Nigel...but it's worth also bearing in mind that this obsession with resolution is actually a new digital phenomenon. In many ways.

When we used film, very few people actually used a film/developer combination that made full use of the lens resolution. I used 400 ASA Kodak Tri-X in FX-39, a combination that gave very sharp grain, but ultra fine grain it was not. If I wanted the highest resolution I would have needed 16 ASA Kodak Technical Pan film, or maybe for something a little less unforgiving of technique 32 ASA Kodak Panatomic-X, or 50 ASA Ilford Pan-F. All these films were black and white.

For colour, the sharpest and finest grained would have been Kodak Kodachrome 25, a slide film. Colour negative films were not in the same league at this time.

The point I'm making is that to make use of all this we need a solid tripod, the slowest ISO value, the optimum lens aperture and flawless technique throughout. Most of us, me included, rarely shoot in this way, making a lot of it a bit academic.
Best regards, John
Pentaxophile
Posted 03/02/2015 - 15:36 Link
I've read some people say things like 'this or that lens was fine on a 12MP camera, but starts to show issues on a modern 24MP sensor'. I am not sure what to make of this, because 12MP is acceptable for 99% of printing purposes.

If image quality issues aren't apparent on a print taken on a 12MP camera, are they really significant printed at the same size from a 24MP camera?

Yes, IDEALLY we would want our lens to outresolve the sensor, but is it worth worrying about so much? So long as it is sufficient for a decent sized print?

By the way, I've not done any standardised tests of legacy lenses, but from simply comparing images I've found some legacy lenses perform much better than new digital lenses I have owned, e.g. I have an old 24mm f2.8 which is much more consistently sharp than I found the CA-prone DA15mm, and I find the F35-70mm sharper than the 18-55 kit lens, with much less CA.
[link=https://500px.com/will_brealey/[/link]
Edited by Pentaxophile: 03/02/2015 - 15:40
McGregNi
Posted 03/02/2015 - 16:00 Link
I can only echo that Will ... In almost every way I see my F35-70 as an ' upgrade' to my DA 18-55 AL WR (of course with the combined focal lengths it's also an extension to the kit lens).
My Guides to the Pentax Digital Camera Flash Lighting System : Download here from the PentaxForums Homepage Article .... link
Pentax K7 with BG-4 Grip / Samyang 14mm f2.8 ED AS IF UMC / DA18-55mm f3.5-5.6 AL WR / SMC A28mm f2.8 / D FA 28-105mm / SMC F35-70 f3.5-4.5 / SMC A50mm f1.7 / Tamron AF70-300mm f4-5.6 Di LD macro / SMC M75-150mm f4.0 / Tamron Adaptall (CT-135) 135mm f2.8 / Asahi Takumar-A 2X tele-converter / Pentax AF-540FGZ (I & II) Flashes / Cactus RF60/X Flashes & V6/V6II Transceiver
Daronl
Posted 04/02/2015 - 11:23 Link
Hi Bill,

You are correct to pick me up on that but what I was alluding too and was a fact is that "back in the day" the number of people who owned and used a " capable camera" and who would regularly print 14x11 or larger, was few and usually limited to enthusiasts and pros.

The digital era however, put millions of cameras out there and for sure none of us will know many people who don' t own a camera that takes pretty good photos; but what happens to those photos ; they are most often presented in small in screen formats, PC,s tablets and cellphones.

The main consumer is social media and the cameras are used as just another communication tool where a decent image for on-screen display is eminently possible and acceptable to this enormous mass market.

We members of such enthusiast sites a PU however, aspire to pursue the enthusiasts and pro standards and the older contingent coming from the Kodachrome 25 and slow film days are probably even more focussed on that ideal.

What would be interesting is for everyone to count up all the pictures the have taken and kept and how many get printed as enlargments.

I would be most surprised if the % of enlargement of the total photos taken even amongst "us enthusiasts" would be better than a minute fraction of the shots.

Whereas , although there was only a minute population of photographers in the film era I suspect balance of enthusiast was larger as a proportion in that smaller population of camera owners.


The large majority of the enormous population of camera owners today who can take good photos, don't try to be enthusiast but are social photographers and will like never print above A4 ( if that)

If they do and they do it would be a poster print run off on a computerised automated printer which will get the best out of the prints., AND THERE IS NOWT WRONG WITH THAT.

The great advantage of the digital era is not only can everyone get an affordable camera but the cameras perfectly suit the social media photography and imaging of today.

In the pre Digital era, Printing was the stock media; holiday albums etc for the causal family photographer where 24 prints could cost half a days wages was the norm.Enthusiast of the day pursued exhibition, competition or professional standards; much harder to achieve with the old film, lens and camera technologies and as I said restricted to the couple of dozen enthusiast in the camera clubs or the pros who were few and far between outside the major cities.

i myself had a pretty successful wedding business and for sure larger prints ( 20 x 16, and bigger) were part of the offer. Photo books today are most common and rarely contain A4 images but will have very attractive high quality collages of much smaller images; and cost the earth.

Both my daughters were married in the last two years, I gave up the will to live when I saw the cost of the story book albums which although they were breathtaking are produced with one tenth of the time and application of a 36 shot album of x 7x 5 and 12x8 prints or some other older enlargement size

As regards the original post re' using film lenses on digital bodies, it was tabled as an observation and discussion aimed at anyone aspiring to a professional standard as a photographer or wanting on occasions to make exhibition quality enlargements.

If we are not going to do that, then use any good lens but ask yourself do you need a K3 or something even more expensive.

The thing I love about Pentax is that a good standard of image quality can be achieved at a very low cost so maybe if aspirations are not to make exhibition standard prints or huge crops it might be more prudent to buy a less expensive body and a more expensive lens; a DA * will turn out breathtaking quality on the least expensive body in the right hands

i wasn't going to write anymore on this thread but Bill did make a good point in his response and was right to pick me up regarding my assertion on printing 14x11 enlargements.

Now I have nothing more to say and feel I am " old codgering here" so I will be quiet on this from today.

It was a good topic though and I thank you all for your contributions and the sharing of your own opinions and experiences from which we can all learn.

Regards





willyolly wrote:
Thanks to Daroni for making some interesting and valid points. However I must take issue with his assertion that "35mm lenses were rarely pushed further to 14x11 prints". Many photographers, both amatuer and professional have produced prints (mainly B&W in my own case) upto 16x20 and above from 35mm for both competition/exhibition and commercial use.

Daronl
johnriley
Posted 04/02/2015 - 11:36 Link
Quote:
Both my daughters were married in the last two years, I gave up the will to live when I saw the cost of the story book albums which although they were breathtaking are produced with one tenth of the time and application of a 36 shot album of x 7x 5 and 12x8 prints or some other older enlargement size

Congratulations to your daughters!

I'm going to have to disagree on the rest of that statement though. producing a wedding book that runs to maybe 120 pages is actually very time consuming and intense. I'm doing one quite soon and Sue and I will be dedicating at least three days of intensive work to the post production of the images.

When I disappear into making the book it will be some time before I emerge, blinking, into the light of day.

That does not disparage in any way those who want to make an album of prints, I've done that too, but we shouldn't dismiss the photo book as a quick and easy option.
Best regards, John
Algernon
Posted 04/02/2015 - 12:47 Link
What's more important for a lens is that it's properly centred. Very few are. Pentax seem poor in this regard.

Example look at the left/right of the boat shot here.....

https://www.pentaxuser.com/review/pentax-smc-p-da-12-24mm-f-4-0-ed-al-lens-revie...

--
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi
johnriley
Posted 04/02/2015 - 13:03 Link
Centering means all the lens elements being assembled so that the centre of each element is correctly aligned to the optical axis. The last general testing I have of all marques relates to 1980s lenses, so it's a bit out of date.

What was revealed then was that Pentax were actually above average in terms of accuracy of assembly. What was also revealed was that even the highest quality lenses could have decentering of even 16% and still deliver superb results.

You can't tell anything about this subject from a picture of a boat. Apart from anything else, boats move, as AP were embarrassed to realise when they stopped using HMS Wellington as a lens test subject.
Best regards, John

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