Images not Sharp Enough

[Kym]

Ok. i am now confused, surely you don't have to factor in crop factor when using this rule, The lens is still the same focal length lens regardless of what sensor it sits in front of, the only thing that changes is the field of view- from the sensor. So why would you need to factor in any adjustment because you are using a smaller sensor. The rules of physics surely don't change just because you are using a smaller sensor. Does someone who uses a D810, which I think has an option to shoot in dx mode all of a sudden have to increase their minimum shutter speed whilst still using the same lens. Seems odd, still the same sensor, just using less of it.

Yes you do. The FL is always the same, but the image area is smaller thus any movement is more obvious (needs a diagram) -- but believe me it is needed to be accounted for (basic geometry)

[ameerat42]

...still the same sensor, just using less of it...

Yes, that is true, but what are you doing with the resulting image? Cropping it. To look at it "closer".
Cropping, whether done in-camera via a crop sensor, or out of camera via software, will render a closer
look at an image.

The rest is

- - - Updated - - -

Humph! What happened to my post??? I thought I had deleted the last line.
It led onto something else that I deleted. OK, now gone.

[Analog6]

Ok. i am now confused, surely you don't have to factor in crop factor when using this rule, The lens is still the same focal length lens regardless of what sensor it sits in front of, the only thing that changes is the field of view- from the sensor. So why would you need to factor in any adjustment because you are using a smaller sensor. The rules of physics surely don't change just because you are using a smaller sensor. Does someone who uses a D810, which I think has an option to shoot in dx mode all of a sudden have to increase their minimum shutter speed whilst still using the same lens. Seems odd, still the same sensor, just using less of it.

And if you haven't been factoring it in that may explain why you feel your images are not sharp enough. Digital photography IS a very steep learning curve, when I first started using a digital SLR (after 40+ years of film cameras) it took me two years to get my head around expose for highlights. I'd nearly always shot slide (transparency) film, where you expose for shadows. And there's a myriad of other small 'hooks' you'll discover along the way.

[arthurking83]

....

Rick I certainly remember the old rule and the simple logic to get the shutter speed in relation to the focal length of a lens.........it was just when I went digital the images taken with an old 35mm film camera somehow always seemed better and sharper than now.

The major (and significant) difference between then and now is that back then you probably never really viewed your (film) images at 100% zoomed view .. ie at the pixel level.

Now the software used to view your images makes it too easy to do this to assess image quality, so it's done as a matter of course.
There's nothing wrong with this, and makes it easy to sift through your images to organise which to archive and which to delete.

I'm not a true believer in the crop factor multiplier rule(of thumb) theory.

[swifty]

Ok. i am now confused, surely you don't have to factor in crop factor when using this rule, The lens is still the same focal length lens regardless of what sensor it sits in front of, the only thing that changes is the field of view- from the sensor. So why would you need to factor in any adjustment because you are using a smaller sensor. The rules of physics surely don't change just because you are using a smaller sensor. Does someone who uses a D810, which I think has an option to shoot in dx mode all of a sudden have to increase their minimum shutter speed whilst still using the same lens. Seems odd, still the same sensor, just using less of it.

Hi Cris,
you are right in that things haven't changed really just by cropping a smaller portion out of a D810 sensor for the same scene. But in effect what you are doing is magnifying what you're seeing when you consider the image as a whole ie. the whole FF image vs the whole DX image.
On the pixel level, nothing has changed. Viewing the FF image at 100% on your computer is the same as viewing its DX crop at 100% because they are viewed at the same magnification when both images come from the same sensor.

Read post #12 of what Lance said.

Essentially what we need to consider with this rule is the field of view and pixel density.
Forget the actual focal length of the lens for a moment and just consider that the wider the field of view, the slower the minimum shutter speed that is required to hand hold for stationary subjects.
The higher the pixel density, the greater the ability to discern movement when you magnify the resulting image.

The 1/FL rule was only convenient because the shutter speeds corresponded relatively nicely to minimum shutter speeds required on the 135 format (FF). It gives people a nice starting point. So for the rule to apply we always need to convert it back to FF equivalent focal lengths. And that's why the crop factor does apply to this rule.


Using the D810 with 36MP as an example. It has a FF sensor and hence no crop factor applies. Compared to a D700 with 12MP (another FF camera), things haven't changed except the pixel density. So there is a greater ability to discern movement when you magnify a D810 image compared to a D700 image but there are actually the same amount of movement for a given lens and shutter speed.
Furthermore, using the same lens (a prime lens for simplicity sake) now on a D7000 (a DX sensor camera with a crop factor of 1.5X) with 16MP. The field of view has changed but the pixel density is very similar to the D810. So with the same shutter speed, there's again the same actual amount of movement. But viewing the D7000 image as a whole is different to viewing the full D810 image. It is more magnified on the D7000 and hence any movement will be more discernible at the whole image level compared to the D810. Hence the need to increase shutter speed correspondingly to compensate. But at pixel level, because the two cameras have very similar pixel densities, essentially the same amount of movement can be detected in both images.
The same prime lens is now on a D5500 with 24MP on a DX sensor. The field of view has not changed when compared to the D7000 so for the same shutter speed, on a picture level they will appear similarly sharp with respect to hand movement because when viewed at the same sized whole-image level they are at the same magnification.
But when viewed at 100% on a computer screen, because of the greater pixel density on the D5500, 100% on screen with a D5500 is at a higher magnification than 100% on screen for a D7000. So there is a greater ability to detect movement on the D5500, but not because there is actually more movement. There are the same amount of movement.

Not sure if I managed to clear anything up or added to the confusion LOL.

[arthurking83]

Great reply Swifty and even tho it may have confused some .. it's basically a perfect reply as to what 'happens'.

My next comment applies only to myself and is not a scientific explanation of the exact physical properties of focal length vs crop factor vs 1/focal length rules and regulations .. but!

Since I've gotten my D800E, I noted in many situations where I can actually shoot at a lower shutter speed(using the same, equal or inferior lenses) than I used too with the D300(lower pixel density) and still see clearer images to a certain degree.
(this is why I don't buy the 1/focal length rule thingy, and especially not the crop factor addendum to it)

The reason is that I very rarely crop an image, and shoot for the entire pixel count to count in the final image.

So where I was using the D300, and wanted a 2000x3000 pixel variant of the final image(the D300 having a pixel count of 4200x2800) but now with the D800E(having 7300x4900 pixels) .. if I still only want/need/use that same 2000x3000 pixel level for a final image, with the D300 the ratio of pixels used compared to pixels created(negative magnification .. or whatever you want to call it) was always higher than it now is with the D800.

So with the D800's 7300x4900 pixels being scaled down(de-magnified, or extended, or reduced .. etc) more than the D300's were .. I see less unsharpness(or blurriness).
The actual image viewed at 100% may be less sharp, or more out of focus .. but because of the reduction of the total number of pixels used to a set number of pixel output .. the image can actually appear more usable!

This is why I laugh when people write up stupid remarks on cameras with ever increasing pixel counts on the basis that we don't need more pixels!(and also make comments to the contrary).

If the photographer is a habitual cropper ... whether by necessity or due to a lack of diligence(this is not a scorn of such practices!!!) .. they probably won't see this effect.
These habitual croppers tho, always benefit from more pixels .. just as they have since time immemorial.
I see this benefit too, up to a point and I don't crop.

And part of the proof of my assertion, is that over the time I've posted images up for review/viewing .. I have never read any comments that my images are unsharp or blurry .. even tho half of them probably are(at the pixel level).
People may not necessarily like the images I've posted, but not one comment made that the images are not sharp.

If you view your images at 100% to discern every pixel in all it's glory .. then the rules regarding focal length and crop factor multiplication probably applies .. even tho it doesn't make any sense.

Andrew(I@M) made a perfectly appropriate point (reply #3) about handholding technique.
Things to take note of: as you age you do lose the ability to maintain a level of steadiness that you may have previously been gifted with. This is a given .. a fact of aging.
It's recently happened to me too .. I used to easily solder the most minute electronic components even just a couple of years back .. now I can barely hold two ropes steady to tie them together
And the other thing to be weary of is over confidence in your technique.
I guess as keenly enthusiastic types about our chosen hobby/job/interest(that is photography), we're probably trying many things to improve it in some way.
Handholding technique is almost certain to be one of those aspects that we all have tried to improve upon in some way or another .. but I also think that we probably get a bit over confident in our ability and (for lack of a better term) 'slack off' a bit ... (guilty as charged!! ).
Or, simply forgetting the basics of what has helped us to achieve this specific improvement in our photography.
That is you've done it .. you've improved your technique, but after some time with this improvement ... which by now a natural movement to you .. is it actually the way you originally started the process of improvement.


To the OP .. working out what shutter speed works best for you is a process of elimination that only you can work out for yourself!
The reason this is, is simple .. we're all too different to have a general broad based rule of thumb that just works!
Some of us are neurosurgeons .. and others probably shake like Shakin Stevens with a degenerative muscular condition.
You can't expect these two disparate types to follow the same set of physical expectations.