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PhrozeN_FisH Jan 12, 2010 10:02 AM

Newbie Lens Problem-pics added
I recently decided to change over from the point and Shoot to DSLR. As a complete novice to DSLR's I did some research and purchased a Canon T1i with 55mm lens kit and added the Canon 70-300mm is usm lens. I have been trying to learn about and experiment with it, but am curious as to whether I may have an issue with my 70-300 lens. Inside shots where the flash is used it will take an exceptional good picture with detail beyond my expectations. When trying to take shots outside the quality of shots I have been getting are somewhat disappointing. I have tried settings from full auto to tv/av settings, auto focus and manual focus, but still have not gotten a good quality shot. There is currently snow cover, and the sky has been overcast. I am wondering if this may be due to lighting conditions outside? About the only difference I can determine between the two conditions are lighting and distance of the shot. More than likely this is due to my inexperience, but hope that someone may provide some insight.


TCav Jan 12, 2010 10:31 AM

Can you post some examples of shots you're not satisfied with?

Mark1616 Jan 12, 2010 1:16 PM

It is likely nothing to worry about and probably a bit of modification to settings will fix things as you have a great lens there. If you can post some samples as TCav says and include any info about the settings used we can try to get to the bottom of things.

shoturtle Jan 12, 2010 2:42 PM

Were you using auto WB. On overcast days, the auto wb may not work as well then choosing the cloud setting on the T1i.

PhrozeN_FisH Jan 12, 2010 4:36 PM

4 Attachment(s)
Thanks for your replies. Yes The auto white balance is on. I hope I can add the pics as attachments otherwise I will have to upload them to photobucket.... The first pic is of a ceramic elephant taken inside at appx. 10 feet. All of the croped images are at 100%. The crop of the elephant shows the moire pattern in the artwork that I had to use a magnifying glass to see. The second is a squirrel feeder at about 25 feet and the third is a cardinal at about 50 feet. I have included the info as I got it from Paint Shop Pro regarding the images. First thing I noticed it that the iso setting is at 1600 for the 2 outside pics. Hopefully, you can give me some insight regarding this... I sure have a ways to go....

All pics taken in full auto:

shutter speed: 1/64 sec
lens aperature:F/5.7
focal length: 250mm
Exposure time:1/60 sec
ISO: 400
Flash: auto on

shutter speed: 1/332 sec
lens aperature:F/6.4
focal length: 300mm
Exposure time:1/320 sec
ISO: 1600

shutter speed: 1/395 sec
lens aperature:F/6.4
focal length: 300mm
Exposure time:1/400 sec
ISO: 1600

ac.smith Jan 15, 2010 9:04 AM

The basic problem with the feeder and cardinal photos is not enough light resulting in the high ISO settings. The 100% crops show about the resolution/noise that I'd expect from that camera at ISO 1600.

Could sharper photos be made under those conditions? Maybe, just. The 1.6x crop factor for your Canon gives you an effective focal length of 480mm when the lens is at 300mm which the usual rule of thumb suggest a minimum shutter speed, assumming good technique and stationary subjects, would be 1/480 sec. If the IS in the lens can get a two stop improvement in the minimum shutter speed of 1/120. Therefore if you had used ISO 800 you would have had a shutter speed of 1/160 and 1/200 respectively. You might have been able to drop the ISO to 640 but with either ISO you are at the lower edge of the envelope and everthing else will have to be right on.

What I can't evaluate in your 100% crops is focus. You were shooting under moderate, low contrast light with fairly "busy" subject so the camera may have selected a different focus point than from where the crops were taken. You should evaluate the full frame to identify the actual plane of focus and see if it was where you wanted it to be.

Lower ISO and good technique could improve those photos. More light would probably result in the photos you want.

A. C.

PhrozeN_FisH Jan 15, 2010 9:13 AM

Thanks for the input ac. I actually took more photos the following day and had great success with the lens. I (my amatuer evaluation) attribute a lot of the problem to light conditions and possibly the angle of the shot related to the late day sun. My short term goal is to improve my knowledge of photography so that I will be able to recognize these problems and adjust to correct them more easily.

peripatetic Jan 16, 2010 8:53 AM

Some possibilities - all related to really just not having enough light available:

1. Shutter speed not fast enough. Ideally 1/500 or 1/1000 is best at 300*1.6~480mm equivalent. But it is an IS lens so 1/400 is probably not the main issue.
2. ISO1600, underexposed - the camera simply cannot give the full kind of resolution you would be hoping for at those light levels.
3. Poor light => slightly off AF performance. Canon AF systems tend to err on the side of speed, sacrificing accuracy where necessary. In the kind of light you had it's possible that the AF simply wasn't getting it as good as it would in better light.

VTphotog Jan 16, 2010 11:22 AM

In general, I agree with others' comments. To get the best from a lens with this focal length, you really should be using a tripod or other type of rest. The cardinal picture looks more as if it is just out of focus, rather than having much motion blur. You can't rely on autofocus when the subject is in branches or surrounded by other objects. Even using the spot focus point in this case, would be unreliable. Learn to use manual focus for these type shots, especially in less than good light.


Shelb Jan 28, 2010 5:23 PM

your filmspeed is the issue (1600). ISO 1600 is usually best used for low low (no) light conditions where you aren't able to use a flash and really just want to grab some quick photos of your experience. Lower filmspeeds will provide cleaner results.

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