Nikon 3500 vs iPhone X...some Questions

[Ed217]

I am new to AP and just learning. I have done telescopes in past decades. Have a new Meade StarNavigator NG 130mm. Trying different photo options including a T-Mounted Nikon 3500 and an iPhone X mount.

So far images taken with the iPhone seem clearer than the Nikon ones. Somehow I expected the opposite and not sure if something basic is wrong in the basic approach.

Any suggestions or comments on where to start?

[JayTee]

A little more info would help. Are you shooting "prime focus" or are you using an eyepiece (afocal) method for achieving an image? Knowing this will help us give you a more accurate answer.

Cheers,
JT

[Ed217]

For the Nikon, it mounts via a T Mount directly to the tube assembly. Focus knob on scope is used as well as a Nikon live view to set at sharp focus

For the iPhone, it mounts via a holder that centers it above the existing eye piece. This is a Gosky Universal Cell Phone Adapter Mount device. You focus using the regular scope/eye piece focus knob. Lining it up above the eye piece is tricky and less than totally stable. It kind of floats in the air directly above the eye piece.

[JayTee]

Thank you for that.

So you are shooting prime focus with the Nikon, and afocal with the iPhone. Now, let's investigate what you mean by "clearer"? Does the iPhone image have better focus, or is it a better image because of the presentation like image size, contrast and other presentation functions that occur within the iPhone? This would also be helpful to know?

Cheers,
JT

[Ed217]

The Nikon image appears lower in sharpness and focus. Has a somewhat of a glow around it. The iPhone is much clearer in most ways.

Today I shot some images of a church during day time, with bricks and window details. Used same placement for both shots with Nikon and iPhone. Same result, ones from iPhone look sharper and more even. Less so for Nikon ones.

[JayTee]

One thing you have to take into consideration when shooting prime focus is that you're shooting at a fixed f-stop. And that is whatever the focal ratio of your scope is. Also, depending upon what mode you're shooting in, manual, aperture priority, exposure priority, will determine if the camera will or will not adjust the exposure time based on the light it is metering. Typically for astrophotos we shoot in manual. This gives us the ability to control the exposure time. So, it sounds to me like you need to experiment with exposure times with your Nikon and also make sure your focus is perfect.

Cheers,
JT

[Juno16]

Hi Ed217,

At first I thought maybe your scope didn’t have enough focuser travel to reach prime focus with the Meade. JT’s suggestion about exposure is a good one, but if your D3500 is like my D3300/D5300, your only option without a lens is Manual.

Since you are seeing the same issue when using a lens and shooting in daylight, it looks more like the camera.

I have a D3300 and a D5300 and they both produce tack sharp images.

Can you hear the autofocus motor running when you partiality press the shutter (with the lens on).

Maybe a camera reset is in order?

Thanks,
Jim

[Ed217]

I am shooting in manual, as the other modes require a lens.

I try different shots first to check for shutter speed to get a good image that's not too bright. I use a remote shutter release to avoid touching the camera to take images (via the iPhone actually).

I take thousands of images with this NIkon, and sharpness has never been an issue. I have up loadable images from today's test with the church if that helps.

[Juno16]

Hi Ed217,

Sounds like something has changed with your camera recently. Can you reset all settings?

Thanks,
Jim

[Ed217]

I can but don't think that is the issue. Just returned from a beach trip where I took hundreds of Nikon pics, none with issues. Somehow this smells like a settings issue with how the camera is set for these pictures via T-Mount. With the iPhone, images are circular. With the Nikon, they are rectangular.

I am new to this area of photo stuff, so learning a lot each day.

[Ed217]

I put both images in the Gallery. Not sure if that is the right place

[Juno16]

Hi Ed217,

The photos really show what you were describing. Now, I understand, however, I have no idea what is causing the soft focus on the corners.

I shoot a dslr on a refractor with a t-ring without any problem. Maybe it is something related to the reflectors optics?

Hopefully someone more knowledgeable about dslr’s and reflectors can comment.

BTW, you can attach images directly to a post. Click the Full Editor button and scroll down to the Attachments tab.

Nikon Image

iPhone Image

Thanks,
Jim

[Ed217]

Appreciate the info. Wasn't sure about attaching directly to posts.

[Ed217]

Ordered a afocal setup for Nikon to see how that works. Also waiting for a replacement tripod as one leg now doesnt hold.

[Juno16]

Hi Ed,

Good luck with the new setup. I am still hoping that someone will offer you some ideas.

I tried both prime focus and afocal with my reflector (Nexstar 130 slt). With the camera mounted directly to the scope, I didn’t have enough inward travel to reach focus. With afocal, vignetting was really bad and the images were washed out. Hopefully, you will have better success.

If you don’t get a response soon, maybe repost with a different title and include the photos. Someone here should know what is causing the issue.

Good luck!

Jim

[JayTee]

It's very rare when we review a daytime terrestrial photo to assess image anomalies. Shooting the moon or Jupiter or better yet a starfield would make it much easier for us to give a reasonably accurate appraisal. BUT as a wild ass guess because you are shooting through a Newt with a DSLR, it looks like a combination of vignetting and coma from the Nikon picture that is not exhibited in the iPhone image. These problems are much easier to see in an astrophoto.

Cheers,
JT

[Ed217]

I expect to get the replacement tripod in a few days. Then with the new afocal gear I can do some night time moon shots at the same time fame with all combos and see how that goes.

[Ed217]

The initial adapter shipped for eyepiece projection was incorrect. Right product number, wrong product. Oh well...a few more days to wait.

[Juno16]

Hi Ed,

I hope you have some success. JT’s advice is spot on. I too was thinking coma, but not being familiar with imaging with a reflector, I did not want to make any suggestions.

Looking forward to your next post.

Thanks,
Jim

[Ed217]

Received the eye piece projection item today...the correct one. Seems to work well so far. Photos are a much higher magnification than with the prime focus setup.

Did have a collumnization issue before too. Did a manual adjustment which seems better so far. Will have a laser device for that tomorrow and do it more accurately.

This is a shot from same church window a few hundred yards away (like before). Lots of wind today so some shake was hard to eliminate even with remote shutter.