APSC has better lowlight than FF/FF is more compact than APSC/APSC math is just a marketing gimmick

[Mark S Abeln]

But FF is clearly smaller than MF?

And the time and budget differences in RND of that format reflect that fact very clearly. I have not mentioned MF for simplicity's sake. Also, MF focal lengths are not the standard of which other systems focal lengths are compared to - Full Frame is.

Too late for this member... and skipped reading 8 words in after your selfie-welcome.

Point taken. I will remove the 'selfie-welcome' as it doesn't really add anything to the discussion. Thanks for pointing it out.

You need to figure out how the indentation feature works on this forum. Here you make it appear as if Janoch is replying to you, which is not the case.

 

[kiwi2]

Put a zoom lens on say f/8 and it will maintain f/8 as you zoom in and out at deferent focal lengths.

For a "constant aperture" zoom, yes. Same with f/2.8 (if the particular zoom lens is capable of f/2.8). But that is not the same thing as the physical aperture changing, since the f/number is not computed with the size of the physical aperture (it uses the size of the entrance pupil).

It also happens with a Canon Rebel kit lens at f/8 from its 18 to 55mm focal lengths. As you zoom in and out it maintains f/8 if that's what you have the camera set on.

At 18mm it has an effective 2.25mm aperture. At 55mm it has an effective 6.87mm aperture at f/8. (I realise the front element is not the aperture on a camera lens)


55mm f/8

The math works out by those numbers. It's also applicable to a basic crown doublet refracting telescope that's aperture is measured by the diameter of the lump of glass at the front of it. It has no other diaphragms or lens elements.


150mm aperture on a 1200mm f/8 focal length

However f/8 on the telescope exposes just the same as f/8 on the Canon Rebel kit lens...


55mm f/8, 1/250 sec, ISO 100


1200mm f/8, 1/250 sec, ISO 100

(note the exact same shade of blue sky)

It all boils down to those numbers. There's no need to over complicate things.

--
https://flic.kr/s/aHskGHoofd

 

[Fergusn]

If you're trying to say what I think you are, its been said 10 years ago in a much clearer form.

Lenses gather light. Sensors don't.

If so, why is all the information on this subject so confused with itself and contradictory?

Perhaps because you are getting your information from the web.

Take a book. One copy is physical, another is an eBook. What difference is there? None. One was sourced from the internet and one wasn't. I do not understand the point you are trying to make here? And if I take it at face value it isn't a point but merely a deflection of my original question.

Larger sensors don't gather more light.

So then why does the myth of Full Frames low light abilities purely from sensor size exist?

Really, it does take a single diagram or equations to show this.

And these are all points that fit within the subject. A subject I have failed to clearly state. My point isn't that sensor size theoretically doesn't have any effect on an image.

But the degree of enlargement needed for viewing the image at a given screen or print size does have an effect.

If the digital file has a resolution and each pixel has the same exposure and the technologies used to generate that pixel were identical then what difference is there no matter how much the image is enlarged?

My point is actually the price disparities between lenses of different formats and the justifications used by manufacturers in their marketing schemes.

Retail prices depend on fixed overheads such as R&D, sales (exhibition stands etc), shipping costs and so on, in relation to numbers sold. The number of FF lenses sold may be much lower than the number of APS-C lenses, so each lens bears a higher share of the overheads.

Exacly my point, however these businesses do not spent 100% of their profits on RND and the volume of sales offsets the cost of development. So then if these businesses didn't use predatory practices targeted towards the most vulnerable customer base (entry level). Do you think us, the consumers would be better off? Or don't consumers matter? If that is the attitude of camera companies I can see the direct relation to profits steadily declining to other industries (mobiles) that care more about users needs being pretty self explanatory.

My point is that with the current technical limitations and with the current state of the market APSC cameras using FF glass with some form of focal reducer is the best current compromise. A compromise no manufacturer will support because it clashes with their marketing schemes. The fact that manufacturers are willing to spend millions on RND (Sony a9) to side skip around an idea that would give us, the consumers, the very best tools possible for the best value. Obviously that is not their motivation - Money is. However, it our responsibility as consumers to dictate market needs and wants.

Now we get down to your real point, which could have been stated at the beginning of this thread, without all the verbiage. You think we should all use APS-C or M4/3 cameras with focal reducers all the time.

Do you feel the advantages in price, current technological limitations of larger sensors (mainly heat management), and the ability to simply remove the Speed-booster instead of adding some form of Tele-converter combined with Mirror-less technology finally catching up to DSLR's and access to an already large range of DSLR lenses isn't a good thing?

If anyone has, for instance, both a Sony A7 series camera and a Sony A6000 series camera, both with 24 Megapixels, and a good 50mm lens, and a focal reducer, it should be easy for them to make a pair of comparison images. A dumb adapter would be used on the FF camera. The lens would be used at f/8.

Depending on the technical differences between the camera they should be directly comparable. Also accounting for the fact no speedboosters above .71x is available for the e mount.

It's probably best to use a studio setup with flash lighting.

And in conclusion I feel there are many points where you are totally right. I have also clearly failed to clearly state my point. That is no ones fault but my own. Sorry.

 

[DeathArrow]

It's all about that F stop yo (like literally).

No, it's not. It's all about entrance pupil:

Aperture & f-stop Myths Debunked: The Importance of the Entrance Pupil

Gerald Undone (Published on Sep 24, 2018)

Try not to contradict yourself.

Thanks for pointing this out!
In an attempt to summarize many concepts down into a single sentence I have done exactly so - Contradicted myself and missed the very point I was trying to make.
I will need to have a big rethink, especially about formatting and the lack of cohesion and direction in my post. Also as has been pointed out I have neglected to write a clear abstract to give members the opportunity to decide if they even want to read the post.
Members have pointed out many smaller errors within the post and foolishly I thought I would be able to edit in corrections without understanding the system that this forum uses. And finally, I have neglected to write any form of clear conclusion.
Sorry to all. Whilst my intentions were to bring discussion to this subject my execution on the matter was simply not good enough. Back to the drawing board.

Have a read:

https://www.dpreview.com/articles/2666934640/what-is-equivalence-and-why-should-i-care

https://www.dpreview.com/learn/2799100497/equivalence-in-a-nutshell

 

[bobn2]

Put a zoom lens on say f/8 and it will maintain f/8 as you zoom in and out at deferent focal lengths.

For a "constant aperture" zoom, yes. Same with f/2.8 (if the particular zoom lens is capable of f/2.8). But that is not the same thing as the physical aperture changing, since the f/number is not computed with the size of the physical aperture (it uses the size of the entrance pupil).

It also happens with a Canon Rebel kit lens at f/8 from its 18 to 55mm focal lengths. As you zoom in and out it maintains f/8 if that's what you have the camera set on.

At 18mm it has an effective 2.25mm aperture. At 55mm it has an effective 6.87mm aperture at f/8. (I realise the front element is not the aperture on a camera lens)


55mm f/8

The math works out by those numbers. It's also applicable to a basic crown doublet refracting telescope that's aperture is measured by the diameter of the lump of glass at the front of it. It has no other diaphragms or lens elements.


150mm aperture on a 1200mm f/8 focal length

However f/8 on the telescope exposes just the same as f/8 on the Canon Rebel kit lens...


55mm f/8, 1/250 sec, ISO 100


1200mm f/8, 1/250 sec, ISO 100

(note the exact same shade of blue sky)

It all boils down to those numbers. There's no need to over complicate things.

--
https://flic.kr/s/aHskGHoofd

Duh. Because that's what exposure is. The real question is why and when exposure is important.

--
263, look deader.

 

[kiwi2]

Put a zoom lens on say f/8 and it will maintain f/8 as you zoom in and out at deferent focal lengths.

For a "constant aperture" zoom, yes. Same with f/2.8 (if the particular zoom lens is capable of f/2.8). But that is not the same thing as the physical aperture changing, since the f/number is not computed with the size of the physical aperture (it uses the size of the entrance pupil).

It also happens with a Canon Rebel kit lens at f/8 from its 18 to 55mm focal lengths. As you zoom in and out it maintains f/8 if that's what you have the camera set on.

At 18mm it has an effective 2.25mm aperture. At 55mm it has an effective 6.87mm aperture at f/8. (I realise the front element is not the aperture on a camera lens)


55mm f/8

The math works out by those numbers. It's also applicable to a basic crown doublet refracting telescope that's aperture is measured by the diameter of the lump of glass at the front of it. It has no other diaphragms or lens elements.


150mm aperture on a 1200mm f/8 focal length

However f/8 on the telescope exposes just the same as f/8 on the Canon Rebel kit lens...


55mm f/8, 1/250 sec, ISO 100


1200mm f/8, 1/250 sec, ISO 100

(note the exact same shade of blue sky)

It all boils down to those numbers. There's no need to over complicate things.

Duh. Because that's what exposure is. The real question is why and when exposure is important.

I'm saying no matter how complex the lens construction is, the numbers work out as if was still just a basic lens like Galileo first used. Aperture size to focal length.

--
https://flic.kr/s/aHskGHoofd

 

[Mark S Abeln]

You post is incorrect.

It matches your post. :-D

I never argue math with the mathematically incompetent, but I will borrow money from them.

Meth use has led to many crazy, long-winded screeds. But I’m not sure if meth users would have any money to borrow.

 

[onlyfreeman]

Are you saying:

1) FF is more compact

2) FF has cheaper lenses

3) Low light image quality is equal (FF is not better in low light, but also not worse)

4) Consumers should stop buying overpriced APS-C lenses

I don't see a problem then, as everyone apparently wants to go FF, even the manufacturers besides Fuji.

Why worry about a few Fuji customers paying more money, just buy a Sony FF like everyone else. A Sony a7 with 28-70mm lens is just £729 new!

 

[kiwi2]

Perhaps because you are getting your information from the web.

Take a book. One copy is physical, another is an eBook. What difference is there? None. One was sourced from the internet and one wasn't. I do not understand the point you are trying to make here?

Anybody can write a blog or upload a youtube clip at virtually zero cost up front. In the past to get a book published you had to find a publisher that was prepared to pay for the printing and distribution, so they tended to put some effort into researching that what you were writing was reasonably correct in the first place.

These days all bets are off.

 

[DeathArrow]

Are you saying:

2) FF has cheaper lenses

For the same IQ and light collecting abbility, that's true.

3) Low light image quality is equal (FF is not better in low light, but also not worse)

That depends on both sensor and lens, so yes, a smaller sensor can achieve the same IQ as a larger sensor if it has a brigher and sharper lens.

4) Consumers should stop buying overpriced APS-C lenses

Everyone should decide for himself

Why worry about a few Fuji customers paying more money, just buy a Sony FF like everyone else. A Sony a7 with 28-70mm lens is just £729 new!

I don't think he is worried, he just pointed to overpriced lenses to prove this point. If you want to achieve a good level of IQ, FF has the best price/performance ratio.

 

[bobn2]

Put a zoom lens on say f/8 and it will maintain f/8 as you zoom in and out at deferent focal lengths.

For a "constant aperture" zoom, yes. Same with f/2.8 (if the particular zoom lens is capable of f/2.8). But that is not the same thing as the physical aperture changing, since the f/number is not computed with the size of the physical aperture (it uses the size of the entrance pupil).

It also happens with a Canon Rebel kit lens at f/8 from its 18 to 55mm focal lengths. As you zoom in and out it maintains f/8 if that's what you have the camera set on.

At 18mm it has an effective 2.25mm aperture. At 55mm it has an effective 6.87mm aperture at f/8. (I realise the front element is not the aperture on a camera lens)


55mm f/8

The math works out by those numbers. It's also applicable to a basic crown doublet refracting telescope that's aperture is measured by the diameter of the lump of glass at the front of it. It has no other diaphragms or lens elements.


150mm aperture on a 1200mm f/8 focal length

However f/8 on the telescope exposes just the same as f/8 on the Canon Rebel kit lens...


55mm f/8, 1/250 sec, ISO 100


1200mm f/8, 1/250 sec, ISO 100

(note the exact same shade of blue sky)

It all boils down to those numbers. There's no need to over complicate things.

Duh. Because that's what exposure is. The real question is why and when exposure is important.

I'm saying no matter how complex the lens construction is, the numbers work out as if was still just a basic lens like Galileo first used. Aperture size to focal length.

--
https://flic.kr/s/aHskGHoofd

Well yes, but that's how it's defined (or was) so what you have is a circular argument. In the end, you're not making any substantive point. Anyway, a compound lens doesn't behave exactly as a simple thin lens, so the idea of 'focal length' is itself somewhat abstract.



--
263, look deader.

 

[MediaArchivist]

Put a zoom lens on say f/8 and it will maintain f/8 as you zoom in and out at deferent focal lengths.

For a "constant aperture" zoom, yes. Same with f/2.8 (if the particular zoom lens is capable of f/2.8). But that is not the same thing as the physical aperture changing, since the f/number is not computed with the size of the physical aperture (it uses the size of the entrance pupil).

It also happens with a Canon Rebel kit lens at f/8 from its 18 to 55mm focal lengths. As you zoom in and out it maintains f/8 if that's what you have the camera set on.

Some zoom lenses will alter the physical size of the aperture as it is zoomed in and out. Other zoom lenses will not alter the physical size of the aperture as it is zoomed in and out. There are "constant aperture" zoom lenses of both types.

In other words, you might be using a constant aperture zoom lens that as you zoom in (increasing the focal length), the aperture itself gets bigger. Or (more commonly), the aperture does not get bigger, but the appearance of it does due to various and sundry optical elements in front of it that magnify what you see.

 

[kiwi2]

Put a zoom lens on say f/8 and it will maintain f/8 as you zoom in and out at deferent focal lengths.

For a "constant aperture" zoom, yes. Same with f/2.8 (if the particular zoom lens is capable of f/2.8). But that is not the same thing as the physical aperture changing, since the f/number is not computed with the size of the physical aperture (it uses the size of the entrance pupil).

It also happens with a Canon Rebel kit lens at f/8 from its 18 to 55mm focal lengths. As you zoom in and out it maintains f/8 if that's what you have the camera set on.

Some zoom lenses will alter the physical size of the aperture as it is zoomed in and out. Other zoom lenses will not alter the physical size of the aperture as it is zoomed in and out. There are "constant aperture" zoom lenses of both types.

In other words, you might be using a constant aperture zoom lens that as you zoom in (increasing the focal length), the aperture itself gets bigger. Or (more commonly), the aperture does not get bigger, but the appearance of it does due to various and sundry optical elements in front of it that magnify what you see.

It's still referred to as the 'effective aperture'. Or just the 'aperture'.

 

[MediaArchivist]

Someone in this thread suggested:

a zoom lens with a constant f-ratio (commonly referred to as a fixed aperture zoom) will change the physical aperture size as you zoom in and out over the focal length range.

That is quite often incorrect.

 

[Holger Bargen]

Your concept may work if you compare APS-C cameras from a company that managed to make good APS-C sensors in terms of noise with FF cameras of a brand that makes quite lousy FF sensors in terms of noise.

Things would look entirly different if you would take a FF camera that uses sensors with low noise even in high ISO ranges.

Otherwise my conclusion form the FF vs APS-C discussion is:

Everything is shifted.

Things turn out to be the same in the medium aperture range if you compare with lenses of same effective focal length (e.g. 150 mm lens on a FF camera and a 100 mm lens on an APS-C camera).

But if these lenses have same maximum aperture of let's say f 2.0, you would get a much smaller DOF from a FF camera. This is one reason why many pros like FF cameras or medium format cameras better than APS-C cameras. Of course you could try to overcome this border by building lenses with larger aperture (let's say 1.2 or even 1.0) but these would be monsters in size and the APS-C advantage is gone.

Also on the other side of aperture range - ad the closed side - there are differences. This time APS-C offers wider DOF because of the shifted effect of an apterture closed to it's maximum setting. But you will be deep into range where diffraction matters with this settings. And, again, you could overcome the APS-C advantage by building lenses with smaller aperture as an option for FF cameras.

You did not mention the effect of sensor design on noise - except of the comparison of a bad FF sensor (in terms of noise) and a good APS-C sensor (in terms of noise):

There are physically important limits for small sensors: you have to build them with much higher pixel density compared to an FF sensor. This means more information flow and thus higher temperature of the sensor as well as higher demand for lens resolution for your camera system. The first aspect will raise you risk of noise - the second aspect will make your construction expensive.

To me the most important reason for shooting FF is: high ISO capability of the sensor and high contrast range even in high ISO ranges. I don't know who my Pentax K1 or the improved PEntas K1ii would compare to your Fuji cameras in this respect - but if my expectaion would be true, it would not support your theory.

Photographic Dynamic Range versus ISO Setting

(edit: Fuji does better than expected - but not better than a good FF camera!)

Best regards

Holger

 

[Gerry Winterbourne]

Actually all we see is that you have failed to understand what you've read and therefore (not surprisingly) come to some wrong conclusions. The fact that you interpret those wrong conclusions into suggesting some sort of conspiracy theory is revealing, too.

There is no conspiracy theory. Go into any camera shop and do some simple crop sensor calculations such as those provided by https://mmcalc.com/ and compare the prices of FF and APSC lenses which share similar focal lengths and F stops.
I have even provided you with some I have done with references clearly stated.

Indeed. And your references are muddled and ill-conceived.

Let's start with your choice of types to compare: you have chosen a single mirrorless APS-C camera as your basis. Compared to DSLRs, mirrorless systems are new and still bearing relatively high R&D costs; there are many threads here asking why mirrorless camera aren't cheaper. And yet you have biased the comparison by taking APS-C mirrorless v FF DSLR.

Not only that, but you have avoided true like-for-like in at least some of your comparisons. Consider your first(my prices are today from WEX, one of the biggest UK sellers.

70-200 F4
APSC Fujinon XF 50-140mm f/2.8

DSLR comparison Pentax 50-135/2.8 £969. Pentax bodies include IBIS so, like the Fuji, this lens is stabilised.

FF EQUIV Fujinon XF 76.5-214mm f/4.2 @ $1,600

£1,449 bundled with a 1.4X TC. The TC alone sells at £375 but clearly the bundle includes some sort of discount; so the lens alone is something like £1,200

FF Canon EF 70-200mm f/4 @ $650

Not stabilised. The stabilised equivalent Canon 7-200/4 is £1,299.

59% Markup

So here the fair comparison (DSLR to DLSR) is actually £330 (34%) the other way.

Nifty Fifty
APSC Fujinon XF 35mm f/1.4

You have said yourself that more refraction requires more correction. Any 35mm lens needs more correction than any 50mm lens.

FF EQUIV Fujinon XF 53.5mm f/2.14 @ $599
FF Canon EF 50mm f/1.8 @ $125

50mm has always been just about the cheapest focal length to design and make. So 50mm lenses are naturally cheaper than 35mm lenses without needing to think about makers weighting their prices. And, of course, the Canon 50/1.8 is a cheap plastic lens.

80% Markup

It's possible to make a host of comparisons, some one way and some the other. Cherry picking ones that suit your case proves nothing except your own bias.

Provide a comprehensive like-for-like comparison or forget your conspiracy ideas.

 

[Fergusn]

Im asking for manufacturers to stop using predatory tactics and pricing on APSC lenses and using crop sensor math as the excuse for such practices.

What does this even mean? What is this "crop sensor math" you seem so upset about?

Every APS-C lens is marked with it's actual focal length and f/stop

Yes and almost all of these lenses have Full Frame equivalent focal lengths stated by manufacturers. I can confidently say that None of these lenses have FF equivalent F stops stated by the manufacturer.

and almost all are sold cheaper than FF lenses of similar specs.

That explains the consistently higher markups vs RND and manufacturing costs in the RRP of all but a few exceptions (such as kit lenses) of APSC lenses

Where is the predatory pricing?

I have stated a very small list of examples in my original post. Although the examples lack the veriation of my research and so I will fix that when I either edit the original post or post a more accurate and technically correct new post and delete (or not, whichever people prefer) this one. Until then I'm learning so much from comments made by yourself and others I think it's in my best interests to keep reading and replying to comments here. As of now this would really help me with editing or re-writing a new post of far higher standards.

 

[Mark S Abeln]

If the digital file has a resolution and each pixel has the same exposure and the technologies used to generate that pixel were identical then what difference is there no matter how much the image is enlarged?

Exposure is measured in lux-seconds, and a lux is equal to a lumen per square meter, and so is a measure of light density and not a total quantity or flux of light. So if one camera has a sensor double the surface area of another, then it will capture double the amount of light, when using the same settings and photographing the same scene and illumination.

Handheld light meters work for any camera, and measure an Illuminance in lumens per square meter.

Exacly my point, however these businesses do not spent 100% of their profits on RND and the volume of sales offsets the cost of development. So then if these businesses didn't use predatory practices targeted towards the most vulnerable customer base (entry level). Do you think us, the consumers would be better off? Or don't consumers matter? If that is the attitude of camera companies I can see the direct relation to profits steadily declining to other industries (mobiles) that care more about users needs being pretty self explanatory.

Actually, in most companies, it is the highest priced goods that have the highest profit margins; while low-end goods have the least, but they make it up in volume. Individual consumers are far more price sensitive than are business and government. Deep pockets lead to large profits.

Preadatory pricing is typically only found in those goods that are what economists call “low elasticity of demand” products, which are those essentials that people will pay almost anything to get: think of education, utilities, and medicine. Luxury goods, such as cameras, are inessential, and consequently have high elasticity of demand, and folks simply won’t buy them if they are too expensive.

My point is that with the current technical limitations and with the current state of the market APSC cameras using FF glass with some form of focal reducer is the best current compromise. A compromise no manufacturer will support because it clashes with their marketing schemes.

Please consider that focal reducers weren’t even available until about 2013 or so, which is after the peak of the digital camera boom. They are late to the party, and weren’t even a consideration for the camera companies.

Now Metabones focal reducers were designed by a top optical designer and are remarkable for what they are, but a lens+focal reducer is still going to be worse than a lens alone.

The fact that manufacturers are willing to spend millions on RND (Sony a9) to side skip around an idea that would give us, the consumers, the very best tools possible for the best value. Obviously that is not their motivation - Money is. However, it our responsibility as consumers to dictate market needs and wants.

The very best values in high technical quality cameras today are the entry-level DSLR APS-C cameras. Amazing machines at a very low price. These are proven, mature designs manufactured in large quantities.

 

[Lee Jay]

You did a great job. Most m43 users understand that’s why we chose the system. My 25mm .95 lens proves your point precisely.

Yes - it's heavier, much more expensive, and effectively slower than my full-frame 50/1.8. And, despite the rambling OP, that point was in there somewhere - that full-frame is smaller and lighter for the same equivalent performance. You only get the reduced size benefit of smaller formats if you accept a slower equivalent system.

BTW, I recently switched from full-frame to APS-c and one reason was the difference in cost between a full-frame 24-70/2.8 and the Sigma 18-35/1.8 for APS-c - equivalent speed for less than half the cost. So it doesn't always work out that full-frame is smaller and cheaper for the same equivalent performance like it does between your 25/0.95 and a full-frame 50/1.8.

 

[Mark S Abeln]

If you cannot fit it in a few paragraphs, you have nothing to say.

I believe the parameters in which the concept is communicated has no effect on the validity of the concept itself. However, I do agree with the comments stating that I have very poorly communicated my point. And that does have an effect on not only the other parties understanding of the concept put forth but also on their interest on the matter.

Philosophers write about the “three transcendental values” of truth, goodness, and beauty, and arguably truth is the most important in the grand scheme of things, followed by goodness and beauty. However, in the human psychological order, beauty is the most compelling, followed by goodness of execution, and only then can the truth perhaps can be perceived by the reader. In human psychology, truth cannot stand alone.

Were your thesis true, which it is not, it still fails because it fails to be rhetorically good, as it is too long to read easily (especially on a smartphone) and it lacks unity, clarity, and cohesion, failing to suddenly illuminate the viewer’s mind like a lightning bolt out of a clear blue sky.

Another way of looking at it is based on Dorothy Sayers’ model of good art, which has three essential elements:

1. The artist’s intent and vision
2. The quality and means of execution
3. The audience’s lively response to the art

If the audience fails to read the text because it is too long, then you have failed. If your vision isn’t true then you failed. If you executed it poorly then you failed.

Sorry. I will rewrite the whole post taking all of these extremely helpful and constructive comments provided to me by the community and see if I can ask for the opportunity change the original post.

Many of us read these forums on our smartphones and read these quickly between other tasks that need to be done.

No, you can’t change the original post, but you can write a new one.