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DPChallenge Forums >> Photography Discussion >> zoom versus shutter speed
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 03/25/2005 02:24:08 PM · #1
This week I've began trying my Nikkor 70-300 f4-5.6D ED.

In my Fuji S5000 I had a 10x zoom that equals 350mm at full telephoto, and the 300mm in the D70 equals 450mm. Getting sharp images at full thel in the Fuji it was not a problem if I had good shuter speeds, like 1/250. I've learned a rule about shutter speed, but I only know the values for wide angles and don't know how it varies with the zoom lengh. The rule was more or less like this: the value of the apperture rounded to the nearest number. For example if it was f2.8 I used 3. The the formula goes: 1/(aperturex20), meaning that if you hand held a cemera at wide end at f2.8 your shutter speed must be at least 1/60.

All this talk is to ask if someone knows how the shutter speed should augmentate according to the zooom (the formula or a table with the values). Because I'm getting a real hard time achieving crisp photos from this lens, and I don't know if it is me or the lens. I've read that it is a bit soft over the 200 mm, and this lens costed me more than the double that costs the 70-300mm G, so have I waisted my money?

I appreciate if someone can help. Thank's
 03/25/2005 02:29:43 PM · #2
I use 1/focal length of the lens as a guideline for shutter speed. I've never seen that aperture calculation before.
 03/25/2005 02:31:36 PM · #3
Originally posted by Nuno:
This week I've began trying my Nikkor 70-300 f4-5.6D ED.

In my Fuji S5000 I had a 10x zoom that equals 350mm at full telephoto, and the 300mm in the D70 equals 450mm. Getting sharp images at full thel in the Fuji it was not a problem if I had good shuter speeds, like 1/250. I've learned a rule about shutter speed, but I only know the values for wide angles and don't know how it varies with the zoom lengh. The rule was more or less like this: the value of the apperture rounded to the nearest number. For example if it was f2.8 I used 3. The the formula goes: 1/(aperturex20), meaning that if you hand held a cemera at wide end at f2.8 your shutter speed must be at least 1/60.

All this talk is to ask if someone knows how the shutter speed should augmentate according to the zooom (the formula or a table with the values). Because I'm getting a real hard time achieving crisp photos from this lens, and I don't know if it is me or the lens. I've read that it is a bit soft over the 200 mm, and this lens costed me more than the double that costs the 70-300mm G, so have I waisted my money?

I appreciate if someone can help. Thank's


It is an entry lens and it is OK for the price. I have it and it works for me. However I wish autofocus would be faster.

Anyway, I think the formula you are using is wrong. Hand held slowest shutter speed is 1/real focal lenth. Meaning at 200mm shutter speed should be 1/200 sec.

Hope that helps.

Nick
 03/25/2005 02:37:48 PM · #4
Originally posted by bod:
I use 1/focal length of the lens as a guideline for shutter speed. I've never seen that aperture calculation before.


The aperture is only relevent as it helps determine the speed of the shutter. It should not be in a calculation for camera shake. The 1/focal. (actual focal length, not equals focal length) is a guideline that works well is you have moderatly steady hands. In other words, if you are shooting 300mm your shutter speed should be at least 1/300 sec. to get a sharp image.
 03/25/2005 02:39:12 PM · #5
Thank's for the help. Are you happy with it Nicolay even at full tele? Do you have the ED version of it? I was convinced by the seller that Ed glass should pay for image qualaty.

03/25/2005 02:45:47 PM · #6
Originally posted by Nuno:
Thank's for the help. Are you happy with it Nicolay even at full tele? Do you have the ED version of it? I was convinced by the seller that Ed glass should pay for image qualaty.


Yes I have ED version. I think it is OK even at 300mm. You can use Panarama tools fix minor problems. I would like it to be faster but that's what you get for this price/size.

Go here to see sample images from various people:
//www.usefilm.com/browse.php?camera_id=&lens_id=68&film_id=&mode=equipment

Nick
 03/25/2005 03:15:06 PM · #7
Originally posted by nsbca7:
Originally posted by bod:
I use 1/focal length of the lens as a guideline for shutter speed. I've never seen that aperture calculation before.


The aperture is only relevent as it helps determine the speed of the shutter. It should not be in a calculation for camera shake. The 1/focal. (actual focal length, not equals focal length) is a guideline that works well is you have moderatly steady hands. In other words, if you are shooting 300mm your shutter speed should be at least 1/300 sec. to get a sharp image.


I'm sure that the 'crop factor' of the camera should be included e.g. with a 300mm lens on a 300D, one should aim for a shutter speed of at least 1/480.
 03/25/2005 03:40:13 PM · #8
Originally posted by AJAger:
I'm sure that the 'crop factor' of the camera should be included e.g. with a 300mm lens on a 300D, one should aim for a shutter speed of at least 1/480.

I'm not so sure.
The exact same image is projected onto the exact same plane as it would be in a film camera, so shouldn't the calculation should be the same as with a film camera? The smaller sensor just takes a crop of this.

It is just a guideline though and needs to be adjusted to suit the individual shooting anyway.
 03/25/2005 04:01:40 PM · #9
Originally posted by bod:
Originally posted by AJAger:
I'm sure that the 'crop factor' of the camera should be included e.g. with a 300mm lens on a 300D, one should aim for a shutter speed of at least 1/480.

I'm not so sure.
The exact same image is projected onto the exact same plane as it would be in a film camera, so shouldn't the calculation should be the same as with a film camera? The smaller sensor just takes a crop of this.

It is just a guideline though and needs to be adjusted to suit the individual shooting anyway.


I kind of think it should - if you are targeting an output that doesn't make use of the full information. If you make a 5x7 print out of an image taken with a 200mm with and without a 1.5 crop, the one with the crop will "enlarge" any camera shake.

But if you are looking at 1:1 pixels, I think you are right that they would be the same shake.

Regardless, the problem can be solved by welding your camera to your tripod.
 03/25/2005 04:37:21 PM · #10
Originally posted by joebok:
I kind of think it should - if you are targeting an output that doesn't make use of the full information. If you make a 5x7 print out of an image taken with a 200mm with and without a 1.5 crop, the one with the crop will "enlarge" any camera shake.

Ah yes, good point.

Originally posted by joebok:
Regardless, the problem can be solved by welding your camera to your tripod.

Or if you have a 300D just heat the bottom until the plastic gets sticky ... ; )
 03/25/2005 05:47:48 PM · #11
Originally posted by bod:
Originally posted by joebok:
I kind of think it should - if you are targeting an output that doesn't make use of the full information. If you make a 5x7 print out of an image taken with a 200mm with and without a 1.5 crop, the one with the crop will "enlarge" any camera shake.

Ah yes, good point.

But ... doesn't that assume the same resolution for both full frame and smaller sensors? Would a 10 megapixel full frame shot not show the exact same shake as a 6 megapixel 10D shot?
If so, where does film - where the 1/focal length calculation is acceptable - fall in all this?
 03/25/2005 06:15:56 PM · #12
Originally posted by bod:
But ... doesn't that assume the same resolution for both full frame and smaller sensors? Would a 10 megapixel full frame shot not show the exact same shake as a 6 megapixel 10D shot?
If so, where does film - where the 1/focal length calculation is acceptable - fall in all this?


I still think it depends on the output - physically light photons are displaced by the same amount inside each of the cameras but since the output process "blows up" the smaller sensor size more, you are more likely to notice the displaced photons in the enlarged version - which would imply that you would want them to be less displaced to start with.

If we were comparing shots between the camera where the images were the same size, we would have to use different focal length lenses - a 75mm on the full frame and a 50mm on the cropped frame. In both cases I think we'd want the 1/75 shutter speed min.


03/25/2005 06:25:11 PM · #13
Originally posted by joebok:
I still think it depends on the output - physically light photons are displaced by the same amount inside each of the cameras but since the output process "blows up" the smaller sensor size more, you are more likely to notice the displaced photons in the enlarged version - which would imply that you would want them to be less displaced to start with.

Right yes, sorry I was only considering the point of capture and not the output.
 03/25/2005 06:38:30 PM · #14
Joebok is certainly correct - if you judge the amount of shake as a fixed amount on a fixed output print size, then you do need to take into account the "crop factor." The calculation for "circle of confusion" takes this into account. In order to calculate it, you need to know the size at which the image will be viewed. The calculation then makes some assumptions about what will and will not be perceptible. Because the enlargement ratio would be different for the full-frame cam vs. a 1.6-crop cam, the CoC changes (for the same print size).
A less, er, confusing way of looking at it is this: if you don't want shake to be visible when a photo is viewed on-screen at 100%, then shake has to be less than the Nyquist limit of resolution for the camera in question, which is 2x the pixel pitch. You'll find that for modern DSLRs it results in a more stringent rule than the ol' 1/focal length rule.
Of course it's not a black/white thing. A little more shake becomes a little perceptible, but only if your sensor, and not the lens, is limiting your resolution. All contributors to reduced MTF are multiplicative (lens, AA filter, shake, etc.)
 03/25/2005 07:08:21 PM · #15
Originally posted by joebok:
Regardless, the problem can be solved by welding your camera to your tripod.


Are you familiar with "The Ultimate Exposure Computer"? :)
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