I want to buy a SLR camera recently, but I always struggle between Nikon D3 100 and D5 100. I hope the photographer can give some advice!

See your questions and problems, mainly entangled in the price and image quality. Comparing the image quality of the two cameras, D3 100 is not as good as D5 100, because the sensor size of D3 100 is 23. 1* 15.4, and that of D5 100 is 23.65438. There is also sensitivity. A high ISO value can improve the imaging quality of digital cameras in dark environment, but the higher the ISO, the more obvious the impact on the image quality and the more noise there will be. Therefore, high ISO sensitivity is suitable for shooting weak light and moving objects. But the image may contain noise and look like particles. On the other hand, although low ISO sensitivity is not suitable for shooting weak light and moving objects, the image is more delicate. The higher the ISO sensitivity, the higher the ambient temperature and the more noise in the image. High temperature, high ISO sensitivity or long exposure may cause abnormal image color. The highest ISO of D5 100 ISO25600 and D3 100 are 12800. Under the same conditions, if the sensitivity of both cameras is adjusted to ISO 12800 to take photos, the noise of photos taken by D5 100 is more than D3 100. This is because the highest ISO value of D5 100 has not reached the upper limit, which is also the function of setting a high ISO value for digital cameras (you can have a look at the comparative evaluation of the sensitivity of these two cameras online). In actual shooting, the ISO value is not too high for ordinary non-professional photographers. The ISO value of the best imaging quality of these two cameras is below ISO800, so D3 100 can fully meet the needs. Except for the sensor, the sensor of D3 100 is a little small, but the image quality is not too bad, which can fully meet the requirements of ordinary people. Even the best card machine is not as good as D3 100. There are also photography technical problems, and the understanding of camera functions and proficiency in camera operation will have a certain impact on image quality; If you don't have certain photographic skills and understanding of the camera, the photos taken with high-end SLR are not as good as the quality of the card machine. In Nikon SLR forum, I saw photos taken by photographers with D3 100 sets of machines, which are very beautiful, no less than those taken by high-end SLR. According to your situation, D3 100 is more suitable. You can practice your hands first. After the photography technology reaches a certain level, economic conditions allow you to change to a mid-range or high-end SLR. This is just my personal suggestion.