[clackers]

By "wasting" the K-1, I'm really thinking about such things as whether the resolving power of such FA/FA* lenses falls short of the resolving power of the K-1 sensor. Maybe all lenses do, I don't know. But having invested a chuck of change in a really good camera, I don't want to "waste" it on lenses that fail to deliver top quality results

???

Do you realize the resolving power of the K-1 sensor is less than the K-3's?

Enough with this YouTube or blogger rubbish about FF as a format.

A FF sensor is cut from the same wafer as an APS-C sensor, it's just twice as large. The pixel pitch and hence resolution is the same.

In fact, you can think of the K-1 as being an oversized K-5.

[monochrome]

If you shoot telephoto the FA*300/4.5 is one of those special Pentax lenses that people hunt down to keep forever.

[mikesbike]

I don't yet have a K-1, but I have had the FA* 300mm f/4.5 for years, using it on both film and on recent APS-C DSLR bodies, and I can say it is one great lens. it has been given an even higher rating optically than the newer version. OTOH, the current DA 300mm f/4 is no slouch either, and you get WR and a quiet AF motor. It is not designated by name for FF use, being DA instead of D-FA, but tests have revealed it to be just an update of an older film lens design, and is fully FF compatible. However, its downsides are- it is larger and heavier than the earlier FA*, the SDM quiet AF motors on lenses from this time period have been subject to failure, and have generally been on the slower side in achieving focus. The FA* 300mm f/4.5 uses the old screw-driven AF, and I have found mine to be exceptionally fast and accurate. The newer lens's quick-shift feature for MF touchup when using AF is rather a moot point here, because the older FA* model has a MF/AF switch right by your thumb where the lens is normally held when shooting.

Another FA lens you might look into is the FA 35mm f/2, which is exceptional whether used for film or for digital, even wide open.

[clackers]

Yeah, on the K-1 I use the FA*300, the FA20-35 f4, and two of the FA Limiteds. I can see the point of the FA 135 f2.8.

There are DA lenses you can use as well, too, don't forget them.

Along with the manual A, M and K lenses, they supplement the modern DFA line that already has every focal length covered from 15mm to 450mm.

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Last edited by clackers; 01-30-2018 at 09:55 PM.

[Fogel70]

D FA is just a name that show that the lens has in some way been designed for digital and that it cover full frame. The exact meaning will differ from one lens to the next.

The first D FA lenses was introduced in 2004 and one was discontinued before K1 existed. D FA 100 macro was replaced by WR version in 2009, but both are basically using the same optical formula as the F version introduced in 1987.

[Paul the Sunman]

The DFA 15-30 is a bit large, or specifically wide, so I only pack it for specific tasks. It's not always in the bag, like the DA15 when using APS-C. However, my standard FF kit when travelling internationally is generally the DFA 28-105 and the DFA 15-30. Considered as a set, that's not too heavy, and it is perfect for general and architectural purposes. Of course, if there's going to be wildlife, I'd take something longer.

[Socrateeze]

???

Do you realize the resolving power of the K-1 sensor is less than the K-3's?

Enough with this YouTube or blogger rubbish about FF as a format.

A FF sensor is cut from the same wafer as an APS-C sensor, it's just twice as large. The pixel pitch and hence resolution is the same.

In fact, you can think of the K-1 as being an oversized K-5.

Yes, I think I do understand that - I was just speaking rather too loosely when using a technical term I really probably shouldn't have. Mea culpe. Like I said, I'm a newbie.

So perhaps you can correct me on this: Suppose you have two lenses of equal optical quality, both projecting the same image but each onto different sensors. The sensors have the same pixel pitch, but one sensor is physically smaller than the other (thus, the projected image is more concentrated on the smaller sensor). As I imagine it - and please remember I'm a newbie - you'll be able to capture less detail on the smaller sensor. Am I mistaken on that?

When asking about whether FA/FA* lenses can match the capacity of the K-1 sensor, what I'm wondering concerns whether those lenses, having been designed for film which (as I understand it) is capable of recording less detail than modern sensors, including (especially) the K-1's sensor, are in general *optically* sufficient to match or exceed the K-1's sensor's capacity for recording detail. In the film era, I suspect that there would have been little point for Pentax to design lenses to higher optical standard than the recording medium (film) was capable of recording. The D FA (and DA) lenses, by contrast, are designed for modern digital cameras, and so I'm wondering whether that implies, *in general at least* (I realise this will vary on an lens to lens basis) an optical improvement over FA/FA* lenses in order to transmit correspondingly greater sharpness, contrast, etc.to match the greater capacities of modern sensors over film.

I'm here to learn, so apologies if these are dumb questions.

Socrateeze

[clackers]

So perhaps you can correct me on this: Suppose you have two lenses of equal optical quality, both projecting the same image but each onto different sensors. The sensors have the same pixel pitch, but one sensor is physically smaller than the other (thus, the projected image is more concentrated on the smaller sensor). As I imagine it - and please remember I'm a newbie - you'll be able to capture less detail on the smaller sensor. Am I mistaken on that?

Yes, you are.

You put same lens, same distance to subject ... you capture exactly the same detail, but a lesser field of view.

This is the origin of 'crop', if you've heard the term.

Pixel by pixel, the data is exactly the same - except the outer half of the image is missing altogether - and the picture is indistinguishable from a software crop of the FF image.

[Socrateeze]

Yes, you are.

You put same lens, same distance to subject ... you capture exactly the same detail, but a lesser field of view.

This is the origin of 'crop', if you've heard the term.

Pixel by pixel, the data is exactly the same - except the outer half of the image is missing altogether - and the picture is indistinguishable from a software crop of the FF image.

I hope I'm not being terribly dense, but I think you've misunderstood the scenario I've described. I said *two lenses*, not "the same lens". And by "same image" I mean you'd see the same image through each lens: same angle of view, everything. It would be like having an 18mm lens with an APS-C sensor and a 28mm lens with a full frame sensor - the image and angle of view is (essentially) the same in both cases, right? This is why I specified that "the projected image is more concentrated on the smaller sensor" to try to make that clear - it's the same image with the same field of view, just squeezed down to a smaller surface area to completely cover the smaller sensor, with no cropping. Wouldn't the 18mm lens with the APS-C sensor capture less detail than otherwise optically identical 28mm lens with the full frame?

S.

[robjmitchell]

Yes, I think I do understand that - I was just speaking rather too loosely when using a technical term I really probably shouldn't have. Mea culpe. Like I said, I'm a newbie.

So perhaps you can correct me on this: Suppose you have two lenses of equal optical quality, both projecting the same image but each onto different sensors. The sensors have the same pixel pitch, but one sensor is physically smaller than the other (thus, the projected image is more concentrated on the smaller sensor). As I imagine it - and please remember I'm a newbie - you'll be able to capture less detail on the smaller sensor. Am I mistaken on that?

When asking about whether FA/FA* lenses can match the capacity of the K-1 sensor, what I'm wondering concerns whether those lenses, having been designed for film which (as I understand it) is capable of recording less detail than modern sensors, including (especially) the K-1's sensor, are in general *optically* sufficient to match or exceed the K-1's sensor's capacity for recording detail. In the film era, I suspect that there would have been little point for Pentax to design lenses to higher optical standard than the recording medium (film) was capable of recording. The D FA (and DA) lenses, by contrast, are designed for modern digital cameras, and so I'm wondering whether that implies, *in general at least* (I realise this will vary on an lens to lens basis) an optical improvement over FA/FA* lenses in order to transmit correspondingly greater sharpness, contrast, etc.to match the greater capacities of modern sensors over film.

I'm here to learn, so apologies if these are dumb questions.

Socrateeze

A lot of old Pentax lenses still perform well because pentax have been using some of the best coatings for a very long time that alow great contrast, colour and reasonable flare control. The other brands have only just caught up. Older lenses do have more CA and less corner sharpness wide open than modern lenses, but most good lenses were pretty sharp in the centre and stopped down. The main area of improvement of modern lenses is in zoom lenses and wide angles. Digital sensors dont like light at oblique angles, ulike film, and so WA lenses now use retrofocal designs to ensure the light hits the sensor at a perpendicular angle.
One of the downsides of modern highly corrected lenses is that out of focus rendering has become less of a priority as it is not Measurable. The only way to judge is to look at lots of images from a lens and see if you like its style. Its hoped the new DFA*50/1.4 will deliver both exceptional sharpness across the frame and also great rendering characteristic, Just like the DFA*70-200/2.8. Lenses like the FA Limiteds are still some of the best lenses ever made, so Pentax certanly has the ability, hopefully Ricoh choose to give them the resources to do it.

[savoche]

I hope I'm not being terribly dense, but I think you've misunderstood the scenario I've described. I said *two lenses*, not "the same lens". And by "same image" I mean you'd see the same image through each lens: same angle of view, everything. It would be like having an 18mm lens with an APS-C sensor and a 28mm lens with a full frame sensor - the image and angle of view is (essentially) the same in both cases, right? This is why I specified that "the projected image is more concentrated on the smaller sensor" to try to make that clear - it's the same image with the same field of view, just squeezed down to a smaller surface area to completely cover the smaller sensor, with no cropping. Wouldn't the 18mm lens with the APS-C sensor capture less detail than otherwise optically identical 28mm lens with the full frame?

S.

Wouldn't the 18mm lens with a 16MP APS-C sensor capture less detail than the 28mm lens with a 36MP FF sensor? Quite obviously the answer will be yes.

But it's awfully hard, and in my opinion not very useful, to try to make comparisons like this. Lenses with different focal lengths will not be identical. If nothing else, changing focal length will change your perspective if you want to have (sort of) the same field of view - which means you can't have everything identical, even disregarding real-world issues as wider lenses having different distortion characteristics etc.

[pschlute]

Suppose you have two lenses of equal optical quality, both projecting the same image but each onto different sensors. The sensors have the same pixel pitch, but one sensor is physically smaller than the other (thus, the projected image is more concentrated on the smaller sensor). As I imagine it - and please remember I'm a newbie - you'll be able to capture less detail on the smaller sensor.

This is like comparing the K1 36MP to the K5 16MP.

I said *two lenses*, not "the same lens". And by "same image" I mean you'd see the same image through each lens: same angle of view, everything. It would be like having an 18mm lens with an APS-C sensor and a 28mm lens with a full frame sensor - the image and angle of view is (essentially) the same in both cases, right?

In this scenario the images recorded on the two sensors would be essentially the same field of view. But the aps-c sized sensor is going to render that image using only 16MP whereas the FF sensor will use 36MP. Obviously the FF sensor will show more detail.

As savoche pointed out it is not really helpful to try and make a comparison like this. The 28mm lens has a much greater magnification than the 18mm lens. That in itself makes any comparison pretty dubious.

[aslyfox]

Yes, you are.

You put same lens, same distance to subject ... you capture exactly the same detail, but a lesser field of view.

This is the origin of 'crop', if you've heard the term.

Pixel by pixel, the data is exactly the same - except the outer half of the image is missing altogether - and the picture is indistinguishable from a software crop of the FF image.

I agree 100 %

best way I can understand the APS-C sensor vs. the " full frame " sensor is this

take a photo of a scene with the FF camera having X MPs

look at the image

now crop the edges evenly all around the image, top/bottom same crop, the sides cropped equally

the result is the image you would have if you had used an ASP-C camera having the same X MPs

the details are not lost in the image, only the size of what is recorded because your recording device - the sensor is a smaller size in the APS-C

both cameras have different size rectangular sensors on which the same amount of light in a circular pattern falls onto

the resulting image depends on what amount of the circular pattern is recorded by the sensor a bigger one in the FF or the smaller one in the APS-C



Full Frame Sensor vs Crop Sensor: Which is Right For You?

Crop Factor Explained

[altis]

One thing to be aware of with film-era lenses is 'hot spots' that can mar certain images. Some old lenses have a particularly flat rear element. This combined with poor coatings and the new shiny sensors can result in a sky blue circle appearing in the middle of high contrast shots. The strength and size of the circle depends on the scene and f-stop.

You can reduce the effect with some effort:
Correcting SMC-F 50/2.8 macro hot spot: Pentax SLR Talk Forum: Digital Photography Review

[clackers]

I hope I'm not being terribly dense, but I think you've misunderstood the scenario I've described. I said *two lenses*, not "the same lens".

Now we're talking about the lens, Socrateeze, not the sensor.

You can easily put a 100mm macro lens on the K-5 and get more detail than a 35mm lens on a K-1 ... that's because your field of view has been dramatically narrowed.

The only way you can compare the two is to control the variables, not change the lens, not change the shooting distance, whatever.