Photo of a helicopter at full zoom.

[Tommo]

Hi guys,

I've recently purchased a D70 with a Tamron 70-300 lens.

Anyway, saw a heli in the sky tonight, so I grabbed a shot on auto mode. This shot was taken in LARGE JPEG, FINE mode, at full extension of the zoom. I have cropped the photo to make it of just the helicopter, and was suprised by the lack of quality. ISO was at 200.

Is this because it's a cheap lens, or is it supposed to be like this when cropped? It's cropped down to about 1/3 of the original size. Not sure if this is normal or not



Thanks,
Tommo.

[Glen]

Tommo, you had the lens at 250mm, probably needed a tripod or monopod at that focal length, though you were at a fast speed (1/2000). I don't have this lens but maybe stopping down to f8-f11 range might help. Maybe a better quality lens would help. Maybe all of the above, but stopping down (reducing the aperture ie bigger number) usually helps. This was shot at f5.6 which I assume is wide open on that lens.

[johndec]

I think what Glen was trying to say (I'm sure he'll correct me if I'm wrong and I'll happily bow to his superier knowledge), is that most lenses tend to be a little bit "soft" at maximum aperture. In the case of this photo, if you'd used a smaller aperture, even though that would have meant a slower shutter speed, the image would have been much sharper. however a slower shutter speed would have blurred the helicopter blades, which I think would have actually enhanced the image and given it a sense of movement.

After you've experimented with the Tamron a bit, I think you will be very happy with it. I've got one myself and have taken (what I think!!) are some very nice pics with it. I just haven't got around to organising a site to host them yet I've taken some very sharp and heavily cropped pics of planes taking off and landing with the Tamron.

No doubt they'll be picked to pieces when I post them

[Nnnnsic]

I'd agree. Whilst I have no experience with the quality of Tamron lenses, the f stop setting is the likely culprit. At 1/2000, you can easily sacrifice some shutter speed for a higher f stop setting.

[Glen]

Johndec, Nnnnsic, spot on

[mudder]

G'day Tommo,
I don't have much learned advice on the pic other than to back up the comment re: blurred blades would have given more of a sense of motion etc., but welcome to the club!

Cheers mate,
Mudder

[JordanP]

I'd agree with all the above, but I'd also add that you wouldn't be able to control the f stop or shutter speed in Auto mode. You would have to use perhaps Aperture Priority or Manual - the shot sees a tad underexposed also as the Auto mode would have been trying to expose for the sky.
Underexposed shots tend to be alot worse with noise & general pic quality

Time is often restricted for such a shot as the one you captured but if you could, I would switch to manual and spot meter off the helicopter itself (this would be overexposing the sky but the heli would perfect).

I love helicopters - I think its a nice shot anyway

Cheers,

[Tommo]

Hi D70users,

Thanks very much for all the responses so far, i'm learning much more already I'll head on out to the airport over the next couple of days, and trying raising my focal setting from 5.6 to 8 - 11, and see how I perform.

JordanP:- I'm a bit confused by what you mean about exposing the sky and heliopter. How exactly do I spot meter the heli itself? I notice on auto mode, the camera always focused on the centre block, which was on the heli itself.

Thanks again,
Tommo.

[JordanP]

Hi, yep sorry I was bit confusing. Your focus would have been fine, but your metering is a different thing. If you look at the D70 forum logo above left you will see a square box with just a dot in the center of it. That is your metering ... the logo is set to spot.

Its roll is to read the light coming from your subject and give you a reading to allow you to set the exposure on your camera. When you are on auto the exposure is set by the camera (not by you) and is based on the information gathered by your metering method.

I don't have my camera here at the moment so other members may be able to tell you which button to push to change the settings.

After reading what I just wrote I'm not sure I have made anything much clearer. Hope it helps anyways.

[gstark]

Hi Tommo, and welcome.

JordanP:- I'm a bit confused by what you mean about exposing the sky and heliopter. How exactly do I spot meter the heli itself? I notice on auto mode, the camera always focused on the centre block, which was on the heli itself.

Try pointing your camera at a clear blue sky and taking a reading, then point it at the road or a footpath, and take a reading ... note the differences ... A cloudy sky will yield different results again.

In auto mode, the camera will be defaulting to matrix metering. While it's focussing in the centre - in this case that's what you want - it's metering on the basis of the full frame, which includes a lot of (bright) sky. That's goig to distort the results, which is not what you want.

The meter reacts to all of this apparent brightness and reduces your exposure accordingly.

If you switch from Auto to A, then change your metering from matrix to spot, your metering will only be based upon the central area (focussed area, actually) and only just a very small region of that area. That will give you a very different EV reading from one that includes a vast expanse of sky.

Traps to watch out for: are you photographing the shaded, or illuminated, side of the helicopter? What about its colour? A white helicopter will yield different results from one painted in navy grey. Red should be similar to grey, but a navy blue of black chopper will present similar exposure issues to those presented by a white one.

Ok ... that deals with exposure.

To me the image looks soft; as others have suggested, stopping down the lens a stop or three should bring you into the lens's sweet spot, and you should see a marked improvement in accuity. If you don't, and the lens is new enough, I'd be contemplating a chat with the vendors.

[Tommo]

Thanks for that clarification I will try all suggestions next time I see something like that, and let you know how I go

Thanks ALL for your help - this forum is a fantastic resource

Regards,
Tommo.