Canon 1200mm+2XEFII+7D

Mr. Photographer

Mr. Photographer

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Lucien Hughes
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Just been looking at super-telephotos for a laugh, This would amount to an equivalent focal length of 3,840mm.

Yes, you read it correctly. Three thousand, eight hundred and forty millimetres.

Can anyone think of a way to reach a larger equivalent focal length?
 
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Mr. Photographer said:
Just been looking at super-zooms for a laugh, This would amount to a focal length of 3,840mm.

Yes, you read it correctly. Three thousand, eight hundred and forty millimetres.

Can anyone think of a way to reach a larger focal length?
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Yes, just crop the resulting image....that's exactly what the 7D is doing.

Just to correct your post a little....
The 1200/5.6 isn't a zoom, it's a fixed focal length, and using a 7D doesn't change the focal length it only crops the field of view. The combination you describe is still 2400mm.

Bob
 
Swap the 7D for a Nikon J1 with adapter.

Equivalent focal length of 6480mm on full frame.

Now put a 1.4x between the 2x and the body. Equivalent to 9072mm on full frame

Totally unusable mind, but just sayin...

(Note, I know about focal lengths never changing, just putting the numbers up for comparison to OP's original figures)
 
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Canon Bob said:
Yes, just crop the resulting image....that's exactly what the 7D is doing.

Just to correct your post a little....
The 1200/5.6 isn't a zoom, it's a fixed focal length, and using a 7D doesn't change the focal length it only crops the field of view. The combination you describe is still 2400mm.

Bob
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I'd so sorry.

The 7D doesn't crop the resulting image, it just has a smaller sensor and therefore uses a smaller portion of the lens's area. Cropping an image isn't the same as using a "crop" sensor.
 
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RichardtheSane said:
Swap the 7D for a Nikon J1 with adapter.

Equivalent focal length of 6480mm on full frame.

Now put a 1.4x between the 2x and the body. Equivalent to 9072mm on full frame

Totally unusable mind, but just sayin...

(Note, I know about focal lengths never changing, just putting the numbers up for comparison to OP's original figures)
Click to expand...

I was trying to avoid using adapters, but sheesh.
 
Mr. Photographer said:
I'd so sorry.

The 7D doesn't crop the resulting image, it just has a smaller sensor and therefore uses a smaller portion of the lens's area. Cropping an image isn't the same as using a "crop" sensor.
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That does depend...
 
Laudrup said:
Have a look at Canon Bob's gear list and ask yourself if he might know what he is talking about.....
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I'm often surprised by how many great photographers there are with pro kit who know almost nothing about the technology behind it. Not to say Bob doesn't, it just doesn't mean much.

Two 1Dx's? AND a 1D4? ...And a 1D3. Holy moly.

All I can ask is... why?
 
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Mr. Photographer said:
I'm often surprised by how many great photographers there are with pro kit who know almost nothing about the technology behind it. Not to say Bob doesn't, it just doesn't mean much.

Two 1Dx's? AND a D4? ...And a D3. Holy moly.

All I can ask is... why?
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Why?
I thought I was just unlucky and kept buying duffers....they'd be okay for a few hundred shots and then just die and I'd have to get another. I now know that there are batteries in these things and they need charging quite often.... an expensive lesson learned :bonk:

Bob
 
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Canon Bob said:
Why?
I thought I was just unlucky and kept buying duffers....they'd be okay for a few hundred shots and then just die and I'd have to get another. I now know that there are batteries in these things and they need charging quite often.... an expensivelesson learned :bonk:

Bob
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:lol:

Coffee / keyboard interface achieved
 
Canon Bob said:
Why?
I thought I was just unlucky and kept buying duffers....they'd be okay for a few hundred shots and then just die and I'd have to get another. I now know that there are batteries in these things and they need charging quite often.... an expensivelesson learned :bonk:

Bob
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CB.

EXCELLENT !

Probably helpful to a lot of newcomers.
 
Canon Bob said:
Why?
I thought I was just unlucky and kept buying duffers....they'd be okay for a few hundred shots and then just die and I'd have to get another. I now know that there are batteries in these things and they need charging quite often.... an expensive lesson learned :bonk:

Bob
Click to expand...

Am I missing something here?
 
Canon Bob said:
Why?
I thought I was just unlucky and kept buying duffers....they'd be okay for a few hundred shots and then just die and I'd have to get another. I now know that there are batteries in these things and they need charging quite often.... an expensive lesson learned :bonk:

Bob
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Haha thats brilliant Bob. Brightened up a rather gloomy afternoon :D
 
RichardtheSane said:
Swap the 7D for a Nikon J1 with adapter.

Equivalent focal length of 6480mm on full frame.

Now put a 1.4x between the 2x and the body. Equivalent to 9072mm on full frame

Totally unusable mind, but just sayin...
)
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See Ivans post ... Link

Pentax Q with an EF 600mm MKII + 2 stacked EF 2X Extenders Total equivalent focal length of 13200mm f/16.
 
Mr. Photographer said:
Am I missing something here?
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Yeah Bob's the Oracle on here, theres not much he doesn't know (especially if its to do with Canon's).

Oh and he has some fab comebacks!
 
But I was right, having a crop-sensor isn't the same as cropping an image from a full frame camera. And I never called anyone a knob.

Oh yeah and if you're going to quote him you might want to change it to "Quote from" ;)
 
Mr. Photographer said:
I'd so sorry.

The 7D doesn't crop the resulting image,
Click to expand...

Actually it does!

Mr. Photographer said:
it just has a smaller sensor and therefore uses a smaller portion of the lens's area.
Click to expand...

It's the smaller sensor that does it.

Mr. Photographer said:
Cropping an image isn't the same as using a "crop" sensor.
Click to expand...

Well to an extent it is. If you used a FF sensor and cropped that you'd get the same result. See below.

full-frame-crop-factor.jpg


Bob knows exactly what he's talking about.
 
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manualfocus-g said:
And yes, using a crop sensor is the same as cropping a full frame image. Except will get more resolution from the 7D shot than, say, a cropped 5D III image.
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Resolution is not the ba all and end all. I'd rather have a larger sensor image with 22Mp than a smaller sensor with 18Mp. The FF camera pixels will receive much more light and the quality therefore better.
 
EOS_JD said:
Resolution is not the ba all and end all. I'd rather have a larger sensor image with 22Mp than a smaller sensor with 18Mp. The FF camera pixels will receive much more light and the quality therefore better.
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Fair point, but if you need an 18mp image (for further cropping, for example), would the 13mp ff crop upscale to 18mp without iq degradation? I'd be interested to try this.
 
back on the original question you could acheive a higher 'equivalent focal length' by putting a dslr on a camera adaptor on a highend telescope like a questar with a high mag eyepiece

the focal length you quote is broadly equivalent to 76x mag (50mm being 1x on a crop sensor) , so if you put a DSLR , then a 2xtc, then an adaptor on a questar with a 46x eyepiece you would have 92x mag or the rough equivalent of 4600mm

Come to that you could put a DSLR on an astonomical telescope with the equivalent of several hundred times mag (the power of big scope being down to their diameter not their magnification per se)- the sky is litterally the limit
 
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Canon Bob said:
Why?
I thought I was just unlucky and kept buying duffers....they'd be okay for a few hundred shots and then just die and I'd have to get another. I now know that there are batteries in these things and they need charging quite often.... an expensive lesson learned :bonk:

Bob
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Classic answer Bob

The problem with cropping into the image especially to the extremes, you need quality optics to resolve the image.
 
manualfocus-g said:
Fair point, but if you need an 18mp image (for further cropping, for example), would the 13mp ff crop upscale to 18mp without iq degradation? I'd be interested to try this.
Click to expand...

Why would you need 18Mp as compared to 13Mp or 22Mp for that matter? A 13Mp will be able to be printed beyond anything the average person would need and IQ will be pretty much indistinguishable
 
EOS_JD said:
Why would you need 18Mp as compared to 13Mp or 22Mp for that matter? A 13Mp will be able to be printed beyond anything the average person would need and IQ will be pretty much indistinguishable
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For further cropping perhaps? Wildlife togs need all the reach they can get, hence the reason many use a crop sensor camera.
 
manualfocus-g said:
For further cropping perhaps? Wildlife togs need all the reach they can get, hence the reason many use a crop sensor camera.
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that doesnt really make sense - a FF sensor with lots more MP will give you more reach through cropping than a cropped sensor 18MP - which is on reason why nearly all top pros shoot with FF
 
manualfocus-g said:
For further cropping perhaps? Wildlife togs need all the reach they can get, hence the reason many use a crop sensor camera.
Click to expand...

big soft moose said:
that doesnt really make sense - a FF sensor with lots more MP will give you more reach through cropping than a cropped sensor 18MP - which is on reason why nearly all top pros shoot with FF
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I think the best approach is to look at the pixel pitch and work from there. A 30D APS-C sensor has the same pitch as a 5D2/1Ds3 so the rule holds at that point but anything newer than the 30D starts to give an advantage....always assuming that the lens is good enough to make use of the additional sensor resolution.

Bob
 
so why do people like Rouse use full frame then ? (question not argument)
 
The argument of 18 MP vs 13 MP is wrong, because you are using a linear scale factor, not area. Ie 1.6 squared which is 2.56.

Hence you should be talking 18 MP vs 8.6 MP. Which is why a lot of people love the 7d and will sorely miss the 1.3x of the 1dmk4
 
big soft moose said:
so why do people like Rouse use full frame then ? (question not argument)
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I suspect he can afford the right lenses to get him close enough and make use of the full frame quality. 800mm on a FF body will usually be better than 600mm on a 1.3 crop.
The pixel density thing would hold true for sensors of the same generation but 30D pixels are a lot older than 5D2 pixels and improvements have been made.

All just IMHO, you understand.

Bob
 
aeronic said:
The argument of 18 MP vs 13 MP is wrong, because you are using a linear scale factor, not area. Ie 1.6 squared which is 2.56.
Click to expand...
True...hence the pixel pitch being the real yardstick.

Bob
 
big soft moose said:
so why do people like Rouse use full frame then ? (question not argument)
Click to expand...

Quality.

Mr Rouse puts huge amounts of time into his field craft, and also drops a significant sum of money on his optics. Between the two you don't need to trade off image quality for the further reach that is offered by a crop sensor.
 
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