The crop factor

[f2zoom]

Some of you out there seem resigned to accept an APS-sized sensor on the upcoming DSLR, on the premise that your ultrawides can be supplanted with new APS-field-sized shorter focal lengths, and that your telezooms will now become supertelephotos.

There's no free lunch. While a 200mm lens used on a camera with a 1.5x crop factor will now provide the same angle of view as the 300mm on a FF-sensor camera, the resolution from the 200mm will suffer accordingly, because of the increased magnification required to produce the same-sized prints:

Whatever the resolution of your lens, when used full-frame, you can divide it by the crop factor, to determine the resolution you'll get from the APS-sized sensor.

And, one more thing. Who wants a camera that only produces good images at ISO 100? (Read the A1 test in Feb '02 Pop Photo)

 

[OzRay]

Some of you out there seem resigned to accept an APS-sized sensor
on the upcoming DSLR, on the premise that your ultrawides can be
supplanted with new APS-field-sized shorter focal lengths, and that
your telezooms will now become supertelephotos.

There's no free lunch. While a 200mm lens used on a camera with a
1.5x crop factor will now provide the same angle of view as the
300mm on a FF-sensor camera, the resolution from the 200mm will
suffer accordingly, because of the increased magnification required
to produce the same-sized prints:

Whatever the resolution of your lens, when used full-frame, you can
divide it by the crop factor, to determine the resolution you'll
get from the APS-sized sensor.

And, one more thing. Who wants a camera that only produces good
images at ISO 100? (Read the A1 test in Feb '02 Pop Photo)

The same people who only had ASA 25-100 film in the 60s-70s (even more restrictive if you go back even further) - those who rose above the technological limitations and managed to achieve results that are still admired today.
--
There are no limitations, only challenges - me (unless someone said it first)

 

[José B]

[text snipped]

There's no free lunch. While a 200mm lens used on a camera with a
1.5x crop factor will now provide the same angle of view as the
300mm on a FF-sensor camera, the resolution from the 200mm will
suffer accordingly, because of the increased magnification required
to produce the same-sized prints:

f2zoom, I claim to be no expert in the relationship of CCDs/focal length/resolution but all of the articles I've read so far only say the benefits as you pointed out, i.e., my 300/4 becomes 450/4 assuming a crop of 1.5. The only downsides I can think of here are:

1.There is no way I can handhold the 300/4 at that focal length. Thus the need for AS, assuming of course the use of a tripod is impractical or prohibited.

2. I have to be careful with the use of flash (of course not with the 300mm) because I could end up too far from my subject.

Whatever the resolution of your lens, when used full-frame, you can
divide it by the crop factor, to determine the resolution you'll
get from the APS-sized sensor.

And, one more thing. Who wants a camera that only produces good
images at ISO 100? (Read the A1 test in Feb '02 Pop Photo)

Ummm, don't go there.

Regards,

José

--
Come and visit me at:
http://www.pbase.com/jmb_56

 

[f2zoom]

There's no free lunch. While a 200mm lens used on a camera with a
1.5x crop factor will now provide the same angle of view as the
300mm on a FF-sensor camera, the resolution from the 200mm will
suffer accordingly, because of the increased magnification required
to produce the same-sized prints:

f2zoom, I claim to be no expert in the relationship of CCDs/focal
length/resolution but all of the articles I've read so far only say
the benefits as you pointed out, i.e., my 300/4 becomes 450/4
assuming a crop of 1.5.

A FF-sensor requires 8x magnification to produce an 8x10; a 2/3 APS sensor would require 12x magnification to produce the same-sized print.

So, if you start with a lens with outstanding (80+ lpm) resolution at the sensor (or negative), the maximum resolution in the 8x10 will be 10 lpm, using a FF-sensor. With an APS-sized sensor, the maximum resolution in the same 8x10 will be 6.67 lpm, or 2/3 of the FF resolutiion.

6.67 lpm in an 8x10 is still very good resolution, but if your lens only resolves 50 lpm at the sensor, or if you want larger print sizes, the disparity between APS and FF becomes increasingly apparent.

 

[José B]

Thanks f2zoom. At this stage I am not looking for a full-frame sensor. If I wanted to shoot FF, I will use my Maxxum SLRs instead.

BTW, what type of Minolta film camera do you own? Type of lenses?

If Mr. Keppler is right on the money, this will be the longest 7-month (between PMA and actual DSLR delivery) period in history for me.

Best regards,

José

There's no free lunch. While a 200mm lens used on a camera with a
1.5x crop factor will now provide the same angle of view as the
300mm on a FF-sensor camera, the resolution from the 200mm will
suffer accordingly, because of the increased magnification required
to produce the same-sized prints:

f2zoom, I claim to be no expert in the relationship of CCDs/focal
length/resolution but all of the articles I've read so far only say
the benefits as you pointed out, i.e., my 300/4 becomes 450/4
assuming a crop of 1.5.

A FF-sensor requires 8x magnification to produce an 8x10; a 2/3 APS
sensor would require 12x magnification to produce the same-sized
print.

So, if you start with a lens with outstanding (80+ lpm) resolution
at the sensor (or negative), the maximum resolution in the 8x10
will be 10 lpm, using a FF-sensor. With an APS-sized sensor, the
maximum resolution in the same 8x10 will be 6.67 lpm, or 2/3 of the
FF resolutiion.

6.67 lpm in an 8x10 is still very good resolution, but if your lens
only resolves 50 lpm at the sensor, or if you want larger print
sizes, the disparity between APS and FF becomes increasingly
apparent.

--
Come and visit me at:
http://www.pbase.com/jmb_56

 

[f2zoom]

BTW, what type of Minolta film camera do you own? Type of lenses?

14mm f3.5 Sigma - lousy close-up, and subject to ghosting outdoors, but relatively low distortion, and adequate sharpness at medium apertures.

16mm f2.8 Maxxum - a terrific lens!

20mm f2.8 Maxxum - see 16mm

28mm f2 Maxxum - see 16mm

50mm f1.4 Maxxum - not as good as the three Maxxum wideangles listed above, but better than the Nikkor f1.4 I owned previously, especially at the widest apertures.

50mm f2.8 Maxxum macro - sharp and contrasty

135mm f2.8 Maxxum - Here's where I really screwed up! I ordered this lens more than a dozen years ago -- right after Minolta dropped it from their catalog. (135mm is my favorite focal length for portraits.) Anyway, I mounted the lens on my camera, and was amazed at how incredible sharp it was -- through the viewfinder! Then, I made the mistake of "inspecting" it, and noticed dust between the elements, so I returned it for a replacement. Weeks went by, before I received the replacement lens. The second lens is not nearly as sharp as the one I returned, and has the same dust between the elements! I thought of asking for the original back, but just wound up keeping this one.

500mm f8 Maxxum Reflex - this is the lens that initially drew me into the Maxxum system. I use it primarily at airshows. It lacks the contrast of a good all-glass lens, but it's a heck of a lot handier to carry around.

24-85 Maxxum i-series - for a zoom, this lens is sharp and contrasty, but there's too much distortion at 24mm to use it for interiors, and 85mm is too short for head shots. I think I would have been happier with the 28-105, and I know I would perfer the 28-135 Canon IS.

100-300 (non-APO) Maxxum i-series - not one of my favorite lenses.

I'm still using the original 7000i I bought in 1989, and the 8000i I bought when Minolta rolled-out the xi series, which I think was one of their greatest blunders. I would have bought the 600si when it was introduced, but it lacked MLP. Had Minolta introduced the Maxxum 7 ten years earlier -- or even five -- I would have bought it. By the time it came out, the handwriting (digital) was on the wall, and I thought, "Why bother?"

Now, I'm just waiting to see what Minolta comes up with in the digital realm.

 

[Randy Z]

And, one more thing. Who wants a camera that only produces good
images at ISO 100? (Read the A1 test in Feb '02 Pop Photo)

The same people who only had ASA 25-100 film in the 60s-70s (even
more restrictive if you go back even further) - those who rose
above the technological limitations and managed to achieve results
that are still admired today.

Every time someone dares to criticize the pet brand of any forum, or point out that it could be better for the money, someone has to trot out the "well if you had any talent or skill, you wouldn't need a sharp lens . . ."

Well, if you hunger for technological limitation, I can make you a pinhole camera from a cardboard box and some tinfoil, and I only want $899 for it.

To want more performance for you money from a lens or camera is not an admission of limited talent.

--
Z-Man

 

[Jim Samuel]

OzRay wrote:
Well, if you hunger for technological limitation, I can make you a
pinhole camera from a cardboard box and some tinfoil, and I only
want $899 for it.

How many megapixels?

Jim

 

[Jim Samuel]

f2zoom, I claim to be no expert in the relationship of CCDs/focal
length/resolution but all of the articles I've read so far only say
the benefits as you pointed out, i.e., my 300/4 becomes 450/4
assuming a crop of 1.5. The only downsides I can think of here are:

No, your 300/4 will have the same field of view as a 450/4 but it will still have the magnification power of a 300mm lens.

If you are 50 feet from your subject with a 300mm lens on a 35mm camera, switching to a 450mm lens will make it appear as if you have moved closer to your subject. That same lens on your digital camera will still appear as if you are 50 feet away.

 

[OzRay]

Every time someone dares to criticize the pet brand of any forum,
or point out that it could be better for the money, someone has to
trot out the "well if you had any talent or skill, you wouldn't
need a sharp lens . . ."

Well, if you hunger for technological limitation, I can make you a
pinhole camera from a cardboard box and some tinfoil, and I only
want $899 for it.
To want more performance for you money from a lens or camera is not
an admission of limited talent.

--
Z-Man

Rant On...

Actually, you read me wrong. I was not referring to just the A1 in my statement, but all small-format sensor cameras as a whole. Small format sensor technology has probably reached it's peak, unless some breakthrough arises. There is no point in berating people for choosing a small format sensor camera such as the A1, S7000, CP5700 etc and saying they are fools for being content with the products limitations. The statement, 'Who wants a camera that only produces good images at ISO 100?' is quite stupid. It's like saying who wants a car that can only do 160kmh (100mph).

If at ISO100 a camera produces excellent photographs and ISO100 is more than sufficient for the job at hand, what is the problem? However, some people on this forum seem to suggest (like Tim the Toolman Taylor) that 'more power' is the only way to go; the next best thing is just around the corner. They never stop to think that they have barely come to terms with what they have and they are already hungering for 'the next best thing'. I never said that I want technological limitation, but I also don't think I need the latest and greatest to keep me happy and producing good photography.

And quite frankly, I do believe that those who constantly harp on about the fact that this digital camera or that digital camera takes krap photos at ISO 800 or ISO 1600, or bleats about noise at same, know diddly squat about photography in general. If such ISO speeds are so all important to them, then they should stay well away from digital, go to film, or get a back breaking personal loan and buy something that will cope. And if you have a look at the Fujifilm DBP for GX680 medium format digital back, shock horror, it only goes to ISO200. Now who would want to buy a US$22,000 camera back (not camera) that only goes to ISO200?

Rant Off...

--
There are no limitations, only challenges - me (unless someone said it first)

 

[José B]

Always great to hear from a long time Maxxum/Dynax user.

BTW, what type of Minolta film camera do you own? Type of lenses?

14mm f3.5 Sigma - lousy close-up, and subject to ghosting outdoors,
but relatively low distortion, and adequate sharpness at medium
apertures.

16mm f2.8 Maxxum - a terrific lens!

20mm f2.8 Maxxum - see 16mm

I'll start here since I own this one. Agreed, this is my favourite 'story-telling' lens. Very sharp. Will become my street photography lens assuming a 1.6-1.7x crop factor on DSLR.

28mm f2 Maxxum - see 16mm

Don't own this one but read great things about it. MIght have to buy one used for street photo if crop comes in at 1.3x.

FF sensor I think is a long shot but will seriously consider 35/2 again for the same purpose.

50mm f1.4 Maxxum - not as good as the three Maxxum wideangles
listed above, but better than the Nikkor f1.4 I owned previously,
especially at the widest apertures.

A few of the posters here rave about this lens. I have the 50/1.7 w/built-in hood. I will read more reviews about the 1.4 because the 50 becomes my main portraiture lens if crop comes in at 1.6-1.7x.

50mm f2.8 Maxxum macro - sharp and contrasty

Don't own this one but it should be great for flower photography.

I have the 100/2.8 Macro, it is so sharp that you have to be careful with it when taking pictures of matured people. Thanks to Photoshop however, I can diffuse unwanted details.

135mm f2.8 Maxxum - Here's where I really screwed up! I ordered
this lens more than a dozen years ago -- right after Minolta
dropped it from their catalog. (135mm is my favorite focal length
for portraits.) Anyway, I mounted the lens on my camera, and was
amazed at how incredible sharp it was -- through the viewfinder!
Then, I made the mistake of "inspecting" it, and noticed dust
between the elements, so I returned it for a replacement. Weeks
went by, before I received the replacement lens. The second lens
is not nearly as sharp as the one I returned, and has the same dust
between the elements! I thought of asking for the original back,
but just wound up keeping this one.

Again, I read great stuff about this lens. Will pass on it since I have a Sigma 70-200/2.8.

500mm f8 Maxxum Reflex - this is the lens that initially drew me
into the Maxxum system. I use it primarily at airshows. It lacks
the contrast of a good all-glass lens, but it's a heck of a lot
handier to carry around.

Mr. Keppler likes it.

24-85 Maxxum i-series - for a zoom, this lens is sharp and
contrasty, but there's too much distortion at 24mm to use it for
interiors, and 85mm is too short for head shots. I think I would
have been happier with the 28-105, and I know I would perfer the
28-135 Canon IS.

I own this lens and I am very satisfied with it. I read about the distortion issues from other users, like a banana-type effect. I don't notice it since I only print no larger than letter-size.

100-300 (non-APO) Maxxum i-series - not one of my favorite lenses.

Don't have this lens. See Sigma.

I'm still using the original 7000i I bought in 1989, and the 8000i
I bought when Minolta rolled-out the xi series, which I think was
one of their greatest blunders. I would have bought the 600si when
it was introduced, but it lacked MLP. Had Minolta introduced the
Maxxum 7 ten years earlier -- or even five -- I would have bought
it. By the time it came out, the handwriting (digital) was on the
wall, and I thought, "Why bother?"

Wise decision. In my case, I just love the Maxxum 9 that I bought a few months ago. Just couldn't pass up the deal for a brand-new one at US $ 869. It has been my favourite Minolta camera.

Now, I'm just waiting to see what Minolta comes up with in the
digital realm.

Hear, here.

Best regards,

Jose

--
Come and visit me at:
http://www.pbase.com/jmb_56

 

[Jim Samuel]

And quite frankly, I do believe that those who constantly harp on
about the fact that this digital camera or that digital camera
takes krap photos at ISO 800 or ISO 1600, or bleats about noise at
same, know diddly squat about photography in general.

I agree. Film isn't so hot at ISO 800 or 1600 either.

 

[lcmacedo]

No, your 300/4 will have the same field of view as a 450/4 but it
will still have the magnification power of a 300mm lens.

If you are 50 feet from your subject with a 300mm lens on a 35mm
camera, switching to a 450mm lens will make it appear as if you
have moved closer to your subject. That same lens on your digital
camera will still appear as if you are 50 feet away.

Right, Jim! I really would preffer a FF sensor, so my lenses will give me the field of view they are designed for. I have a Sigma 28-105 and a Maxxum 100-300, which cover 95% of my needs. If there is a crop factor, I'have to buy an 18 mm ( very expensive ) and really don't care much for a 450 mm ( with less resolution ).

Lucas

 

[Daniel (NL)]

If there is a crop factor, I'have to buy an 18 mm ( very expensive )

The Tamron 19-35 3.5-4.5 and Tokina 19-35 3.5-4.5 are not that expensive, and are (supposed to be) pretty good. I have the Tokina myself, does have not such bad distortion, not much vigneting (non with crop factor), and pretty sharp too. Just a tip in Minnie sells what we want.
--
Daniel

 

[Randy Z]

Rant Off...

Good rant, well put, I do know what you mean! I just couldn't resist the pinhole comment.
BTW, it's 1 pixel analog.

--
Z-Man

 

[RaduT]

....

And, one more thing. Who wants a camera that only produces good
images at ISO 100? (Read the A1 test in Feb '02 Pop Photo)

Phographers have used for years - and with excellent results! - films with ISO 50 and 64. Besides, the A1 ISO 100 seems to be somewhere in between 100 and 200.

..and I still don't see the point of your statement!

--
Radu
...........................
Dubito, ergo cogito...

 

[toughluck]

There's no free lunch. While a 200mm lens used on a camera with a
1.5x crop factor will now provide the same angle of view as the
300mm on a FF-sensor camera, the resolution from the 200mm will
suffer accordingly, because of the increased magnification required
to produce the same-sized prints:

f2zoom, I claim to be no expert in the relationship of CCDs/focal
length/resolution but all of the articles I've read so far only say
the benefits as you pointed out, i.e., my 300/4 becomes 450/4
assuming a crop of 1.5.

A FF-sensor requires 8x magnification to produce an 8x10; a 2/3 APS
sensor would require 12x magnification to produce the same-sized
print.

So, if you start with a lens with outstanding (80+ lpm) resolution
at the sensor (or negative), the maximum resolution in the 8x10
will be 10 lpm, using a FF-sensor. With an APS-sized sensor, the
maximum resolution in the same 8x10 will be 6.67 lpm, or 2/3 of the
FF resolutiion.

6.67 lpm in an 8x10 is still very good resolution, but if your lens
only resolves 50 lpm at the sensor, or if you want larger print
sizes, the disparity between APS and FF becomes increasingly
apparent.

Only if the pixel pitch is the same between the FF and APS-sized senors, that means that a 6 megapixel sensor's counterpart - that means a 13.5 megapixel sensor. Then you could actually compare resolutions and mention magnifications. Philips had been manufacturing sensors for Contax, and their resolution was 6 megapixels.

As for resolution... 80 line pairs per millimetre is already near the peak of sensor's resolving power - it means 5760 pixels horizontally, 3840 vertically, only 22 megapixels. And mind you, an APS-sized sensor still resolves at 80 line pairs per mm, only there's less of those millimetres to go around with. Now, if you were to talk about line pairs per picture height/width, there would be more point to that. Still, 80 line pairs/mm means the sensor peaks out at 3840 pixels horizontally, 2560 vertically, 9,83 megapixels total. IS the megapixel race NOT over? Unless camera and lens makers come up with something new that would outresolve such a sensor, they will simply not need more resolution - oh, unless they wanted to outresolve lenses on purpose and get ride of colour moire and aliasing artefacts.
--

'Nuclear powered vacuum cleaners will probably be ready within 10 years,' Alex Lewyt, of the Lewyt Corporation, a vacuum maker, predicted in The New York Times on June 10, 1955.
--- A warning to all technophiles

 

[toughluck]

....

And, one more thing. Who wants a camera that only produces good
images at ISO 100? (Read the A1 test in Feb '02 Pop Photo)

Phographers have used for years - and with excellent results! -
films with ISO 50 and 64. Besides, the A1 ISO 100 seems to be
somewhere in between 100 and 200.

Yes, 2/3 stops faster. Add AS (good for 1-2 stops, let's say 1 1/3), and you effectively have an ISO 400 sensor without AS , but also without noise problems. If noise at ISO 200 does not bother you, you have ISO 800 equivalent. Now, how can the digital Rebel (EOS 300D) with standard lenses beat that? Look at the chart Phil drew for the 828 review - A1 has only two times more noise than 300D. If you care enough for your pictures, you'll get more than you wanted if you shot with RAW (and avoid in-camera processing).

..and I still don't see the point of your statement!

Me neither, but it's a good discussion-stirrer...

--
Radu
...........................
Dubito, ergo cogito...

--

'Nuclear powered vacuum cleaners will probably be ready within 10 years,' Alex Lewyt, of the Lewyt Corporation, a vacuum maker, predicted in The New York Times on June 10, 1955.
--- A warning to all technophiles

 

[RaduT]

...
Well, if you hunger for technological limitation, I can make you a
pinhole camera from a cardboard box and some tinfoil, and I only
want $899 for it.
To want more performance for you money from a lens or camera is not
an admission of limited talent.

--
Z-Man

If you can justify it, w or w/o talent, then you should be looking at dSLRs. I presume that the major hurdle is to understand what's technically feasible and what not. And until recently I was in this camp too, rejecting all "prosumer" digicams due to their shortcomings when compared to my film cameras.

In fact I bought and returned several digicams, starting with Toshiba PDRM70, and then Canon G3 and Oly 5050. Meanwhile, I'we educated myself, learnt a bit more about what's in 2/3" sensor and what SNR (signal-to-noise-ratio) it can deliver, pixel size and resolution, looked at my needs, discarded the F828 and ended up with the A1.

No, A1 it's not going to replace my Nikon F100, but it's a very useful tool and I think it's worth the money I spent on it.

Could it be better? Perhaps, don't know at what cost though, sometimes a S/W release it's more expensive than redesigning completly the H/W! On top of that, there will always be customers out there who will never get the F/W upgrades or encounter problems with the upgrades, therefore the choir of complaints will never cese.

Enjoy the time you spend taking pictures and save money for the next gadget loaden camera which the market will throw at you!
--
Radu
...........................
Dubito, ergo cogito...

 

[f2zoom]

And, one more thing. Who wants a camera that only produces good images at ISO 100? (Read the A1 test in Feb '02 Pop Photo)

..and I still don't see the point of your statement!

Me neither, but it's a good discussion-stirrer...

It's based on a still-developing consensus around the theory that densely packing APS-sized sensors [instead of spreading the pixels out on larger {FF} grids], may a causative factor toward the noise issue at higher ISOs.

Does anyone out there own the mythical Contax Digital? This is supposed to be a 6 MP FF camera, that was announced several years ago, but I've never seen it tested, don't know anyone who owns one, and don't see it advertised anywhere. It would be interesting to learn about its performance at higher ISOs, if the camera, in fact, exists at all.